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Theoretical Gpu Overclock


neighbor
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top stable speeds for me atm are:

315mhz GPU, 155mhz FSB

Be cautious with this, and always flash it to a modchip, in case something goes wrong, you will be able to remove the modchip and boot off the TSOP.

 

Last times XblastOS.xbe refuses to boot, after disconnecting the DVD drive, it started to boot again. XblastOS is tricky, not always booting and not always flashing.I have 2 aladdin modchips, one always untouched with IND bios, other for different stuff like this, so if with second modchip XblastOS.xbe is not booting (which happened to me a lot of times), I boot with the healthy untouched aladdin, launch XblastOS.xbe, go to flash from HDD, change carefully the modchip to the problematic one, then hit flash and it goes. This way it worked.

Edited by neighbor
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On 3/25/2019 at 3:06 PM, y0urh34d said:

So far the only thing I tested was Goldeneye on N64 emulator and the game so far at the start, there is almost no performance hit with 720p with the overclocks. I'll test some more stuff if anybody wants to know the performance of any other emulators or whatever. Maybe I'll test my other 1.4ghz xbox which is a v1.4 with that different gpu and see what I'd get.

bud, any updates?

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19 hours ago, neighbor said:

bud, any updates?

Sorry for my lack of updates, So far I've just tested Crazy taxi 3, Crash Twinsanity, manhunt and GTA 3 and VC all at 720p.

Crazy taxi it didn't improve framerate much (unplayable besides the 1st level), Crash twinsanity was improved with a few dips here and there (better than before), the same can be said for Manhunt and GTA 3 and GTA VC it removed most of the frame dips. Unfortunately for 3 & VC, they're still at 733mhz timing not at 1660mhz timing so everything is now more than double speed.

What are some other emulators that struggle on even the 1.4ghz cpu modded xbox's. 

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2 hours ago, y0urh34d said:

 VC at 720p

can you please upload the xbe somewhere? and what version is that?

regarding the NVCLK speed, I started to see more improvements after 290mhz, before that, they were not really noticeable.

Edited by neighbor
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27 minutes ago, neighbor said:

can you please upload the xbe somewhere? and what version is that?

regarding the NVCLK speed, I started to see more improvements after 290mhz, before that, they were not really noticeable.

I have to turn off widescreen to not get the double screen and that was just the normal settings in ogxhd with the window view ticked. Yeah unfortunately my xbox doesn't clock up as much as others on the gpu side probably due to the cpu clocked so high.

Anyway this is the xbe, but it does double screen when the xbox has widescreen enabled which I haven't been able to fix.

defaultXHD.XBE

Edited by y0urh34d
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24 minutes ago, neighbor said:

try to leave the FSB at 133, and just raise the GPU clock, also add more cooling.

That's a very good point, since overclocking the FSB also overclocks the RAM. The quality of the RAM varies significantly in all Xboxes due to the fact Microsoft allegedly sometimes used faulty RAM that cannot run at the full designed spec (and used a test on each startup to slow down faulty RAM to make it work reliably at the cost of performance). I have been testing this on my Trusty revision 1.0 Xbox (1.4GHZ CPU with 128MB RAM). I do not think Trusty replaced the original 64MB RAM, I think he just added new RAM in the missing places, so therefore if the original RAM is low quality, that limits the speed already. I cannot overclock the FSB beyond 144 without lockups. A tad disappointing is that the NVCLK will only go as high as 277 without lockups. If I try anything over 290 I will get black screen on boot. Thus I am not likely to see much noticeable improvement. However I did find that using a different PSU will also have a slight effect too- my old delta PSU would allow stable 268 NVCLK, a Foxlink PSU will allow as high as 277. Both PSUs get quite hot when doing this mod and when lockups occur I have to wait for the PSU to call down otherwise the Xbox will not completely boot (either a black screen or a frozen boot animation will occur). As I've got cooling fans on both the GPU and CPU there's not much more that can be done except to boost the speed of the exhaust fan.

I will try this again on my N64freak 1GHZ 128MB Xbox (revision 1.4) when I get the chance and post in here again. I have a feeling I will have better luck on this one since N64freak tends to really treat these boards with much better respect to detail. I also have another revision 1.0 Xbox with a stock 733MHZ CPU and 128MB to test with but I do not have it in my house at the moment.

In summary: all components will have a significant impact on your success with this mod! If you have the skills and patience, try replacing *all* your RAM with known high quality modules (too nerve racking for me to do myself!). Also also: check that your PSU has enough breathing space. Having a SATA adapter board with all those extra wires for it can't help if you stuff the wires over the top of the PSU. Yes there's hardly any space but try relocating most of those wires underneath the hard drive tray.

aaaand Submit...

Edited by samspin
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3 hours ago, samspin said:

overclocking the FSB also overclocks the RAM. The quality of the RAM varies significantly in all Xboxes

Is there any info regarding the quality of RAM chips in Xbox?
I doubt N64Freak is replacing all the RAM chips when doing the upgrade. Even the way soldering looks on his works is noticeable, and points to - he was just adding RAM chips, and not replacing all of them. If you have a board from him, you should see that the additional chips have thinner soldering than the stock ones.

A guy on discord told me he overclocked his stock 733mhz CPU to 870mhz (158fsb), and the NVCLK to 315mhz, the board is a 1.2. So that are good news, meaning not only 1.0 Xbox-es can handle this high overclocking, atm would be nice to understand what is actually the reason why some Xbox-es can't go high enough to reach fsb 158, nvclk 315.

 

BTW, the cooling power supply is external in my case, no idea if it means much for this mod.

Edited by neighbor
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I don't replace the stock ram and add the extra 64mb like anyone else does.

If there is any interest i can source a couple of the QC-40 Ram chips and do a Board that also has the stock 64mb replaced. Would be interesting to see if that makes a difference compared to the stock QC50 ram. A 128mb Hynix Ram board would also be an interesting test subject here.

Using an ATX adapter and a standard ATX PSU would definitely solve any PSU heating problems. Any ATX psu should be able to supply a lot more current and probably also a cleaner voltage than the cheaply built and ageing xbox psus.

To get the FSB even higher the CPU probably needs better cooling and it might help to raise the CPU voltage a little.

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N64freak: Thank you for clarifying that you leave the stock ram installed! I still believe I will have better luck on your board because it looks to have been much better looked after!

31 minutes ago, neighbor said:

Is there any info regarding the quality of RAM chips in Xbox?

I got the info regarding not all stock RAM being equal from the following: a paper on the Xbox security system, and slides from a presentation of the paper. Both under the heading "RAM initialization". Microsoft took *any* RAM that Samsung offered in order to keep production costs low, including ones that won't run at the full spec. This happens a lot in manufacturing yields where some modules produced aren't quite up to the intended spec and would otherwise have to be scrapped or instead sold advertised at a lower top speed.

https://events.ccc.de/congress/2005/fahrplan/attachments/674-slides_xbox.pdf

https://cs.oberlin.edu/~ctaylor/classes/341F2012/xbox.pdf

According to the slides, the Xbox startup routine tries placing a small piece of data in the RAM and testing retention at 200MHZ, then 195, then 190, and so on until the RAM either passes the stability check or will not clock down further. This appears to be the pseudo-code used:

"POKEPCI MEM_CNTRL, 200 POKE 0, 0xAAAAAAAA ACC = PEEK(0) IF ACC = 0xAAAAAAAA GOTO END POKEPCI MEM_CNTRL, 195 POKE 0, 0xAAAAAAAA ACC = PEEK(0) IF ACC = 0xAAAAAAAA GOTO END POKEPCI MEM_CNTRL, 190"

Thus this is why I believe the RAM quality plays a part in how successful one can be when attempting to overclock. It's therefore pot luck on this aspect. I would imagine that if you go to a reputable seller for new RAM, these modules would run at the full spec they were designed for.

4 minutes ago, neighbor said:

hope a picoPSU can handle that. You have any ideas on how to raise the voltage on CPU or GPU?

Wow, just searched for "PicoPSU" and I am very impressed! I would love to try one of those. It's a shame that XBOX to ATX adapters are no longer sold but I imagine with a lot of perseverance I could probably cut up a plug and fit the wires to the correct pinout myself.

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20 minutes ago, samspin said:

"POKEPCI MEM_CNTRL, 200 POKE 0, 0xAAAAAAAA ACC = PEEK(0) IF ACC = 0xAAAAAAAA GOTO END POKEPCI MEM_CNTRL, 195 POKE 0, 0xAAAAAAAA ACC = PEEK(0) IF ACC = 0xAAAAAAAA GOTO END POKEPCI MEM_CNTRL, 190"

wow, that's some nice info. ATM, have to try raising voltage on RAM chips, as Ryzee suggested and also search for QC40 variant of the RAM as they are described to have top speed clocked at 250mhz.

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1 hour ago, N64 freak said:

The 5V rail on the PicoPSU is a little weak for the Xbox

did you come to this conclusion after testing a 1.4ghz xbox motherboard?

also, need to check, maybe there are different versions of picoPSU with more power.

update:

checked, there are different models of picoPSU, will buy a 250w and see how it performs, but it won't be soon.

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2 minutes ago, N64 freak said:

@samspin I made a design for an ATX to Xbox adapter and that works just fine. The PicoPSU is a little weak for the Xbox. The 5V rail on the PicoPSU is a little weak for the Xbox. So at least for testing i would recommend to either use the original PSU or a standard ATX PSU.

Thanks for pointing that out! I have in the meantime as a result of my curiosity sought some aftermarket PSU's from the RichsPSXparts to see if these make any difference.

5 minutes ago, neighbor said:

wow, that's some nice info. ATM, have to try raising voltage on RAM chips, as Ryzee suggested and also search for QC40 variant of the RAM as they are described to have top speed clocked at 250mhz.

It's worth noting that the RAM initialization code is within the secret ROM in the Southbridge (MCPX) and NOT in the BIOS itself. It is therefore in normal circumstances not replaceable. However... there is hope. The secret ROM (both versions) has been dumped. According to the security paper, the secret ROM was circumvented by making use of a legacy CPU feature (the A20 gate) in order to force the Xbox to start at an address in flash rather than in the Southbridge, and placing a small dumper application directly in flash.

http://xboxdevwiki.net/File:Haxar-a20m.jpg shows you only need to solder one wire to accomplish this.

Both versions of the MCPX dump are available on XBins.

So... in theory one could do the same trick and place a modified startup routine directly in flash, along with a modified 2BL to concatenate the contents of the secret ROM, albeit with edits to set a higher RAM clock speed along with the physical RAM replacement with QC40 modules. Of course you would have to ensure any BIOS image you are writing to flash takes this into account. Uh, this is getting very complex isn't it? I know I haven't got the programming background to pull this off, but it does give you an idea of what to look for if one did have the programming expertise to try this. Even without this however, just doing the physical modifications would be an interesting test.

I will be testing the XBOverclock on my N64freak board once I have some more Aladdin Modchips, hopefully in a couple of days. I do not want to brick it by writing directly to the TSOP. It's pretty easy to take the flash chip out of an Aladdin board and use a USB PIC programmer to flash externally to try again. Removing the TSOP from the Xbox itself if I were to put an unbootable image on it and reflashing that externally would be much more of a challenge (well, getting it off the board is one thing, getting it back on without damaging those delicate pads... urgh)

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44 minutes ago, samspin said:

http://xboxdevwiki.net/File:Haxar-a20m.jpg shows you only need to solder one wire to accomplish this.

I can do that on the hardware side, but on the code side I'm lost. Isn't the RAM overclocking already when the FSB is increased? as WulfyStylez says in the description:

"Currently, NVCLK (NV2A GPU core) and FSB (system front-side bus, used by CPU, SB, ...) clocks can be adjusted."

BTW, isn't that MCPX code relocation a potential way to let Xbox see RAM chips of bigger capacity?

Also, most of the games I tried in 720p, have a lot of lag when too much effects appear, like reflections, shadows, dust, smoke. fog. Do you have any ideas if there are DirectX8 calls which are responsible for reflections or shadows, which can be disabled or changed (in the default.xbe) in a manner to reduce them in-game, and make the game run smooth?

 

oh yeah, a lot of noob questions, as my skill and knowledge are very basic.

 

update:

one of my mates suggested to replace all the capacitors on the motherboard and probably PSU, to check if it will let some Xbox-es go higher than 290mhz on NVCLK.

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REPORT:
I have 2 boards, ONE which was used for the overclocks, and TWO which was not touched until now, both with 1ghz CPU.

Board ONE was clocking to NVCLK 315mhz, FSB 158mhz, so I decided to overclock board TWO, but it was stuck at NVCLK 270mhz, FSB 140mhz, anything higher just froze the Xbox. The first thought was, the need to replace capacitors, so all the caps from board ONE were desoldered and put on board TWO. Even after this, board TWO was showing the same exact problems, no changes. 

Then desoldered the additional RAM chips from board ONE and soldered to board TWO - same thing, same problems, can't clock higher. The last attempt will be to desolder the remaining 4 stock RAM chips from board ONE and solder them in place of stock RAM chips on board TWO, so all the RAM chips which were on board ONE - will be planted to board TWO.

 

other notes:

- same PSU used for both motherboards

- additional cooling powered by outside source (not from Xbox motherboard)

- only SMD capacitors were not replaced, most of them are near the video and network connectors, and only one near the MCPX chip

- both boards are 1.0 rev

- was overclocking only FSB and only NVCLK, both ways the top speeds were same as if they both were overclocked simultaneously

expectations:

- to place all the RAM chips from board ONE to TWO and see if the RAM chips are the reason of this issue

 

any thoughts?

 

ps. Can anyone try the overclock on a stock Xbox with 733mhz CPU?

Edited by neighbor
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some other thoughts regarding RAM:

N64F said he soldered 8 Hynix RAM chips to a Xbox motherboard (other than 1.6 rev obviously), does it mean that there is posibility to install some other chips other than the stock ones which came in Xbox-es? maybe the MCPX rom just checks the RAM chip's speed only?spacer.png

HY5DU283222AQ family datasheet

will try to buy HY5DU283222AQ from here

 

Quote

if there is any interest i can source a couple of the QC-40 Ram chips and do a Board that also has the stock 64mb replaced

Sure N64Freak, it's very interesting, please do.

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some other thoughts about RAM chips:

so if the South Bridge and RAM are overclocking with the raise of Front Side Bus, and their default stock clock is 200mhz (when FSB is 133mhz), then they are probably clocked at 237mhz (when FSB is 158mhz)

158/133=1.187

200*1.187=237.4

that's way higher than the declared top speed for this chips, I won't blame MS for this.

Does it look right, or I am missing something?

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buds, can anybody link to a tutorial on how to setup a devkit environment and be able to monitor the use of machine resources during runtime? I already have a Xbox with IND 5003 bios which was set up to boot the default.xbx, system also has 128mb ram and an attached hard drive which boots the debug kit dash. Want to see what are the parts which can't handle Halo in 720p.

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2 hours ago, Blobby85 said:

Could you share the xbe for Halo in 720p? Never managed to get this right by myself

this thing was shared to me and told to not share it to anyone, I will ask the guy if he changed his mind. The idea behind this, is to finish the optimisations then release, but need to ask the guy.

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  • 2 weeks later...

Firstly, ensure you are using a modchip to boot from, preferably one that has a removable flashrom (like the Aladdin XT). Another option is the SmartXX, since most versions of those have recovery boot options. Reason being, if you set a clock rate too high, the Xbox will not be able to boot fully and will be useless. If using the Aladdin XT I would recommend a USB PIC programmer and a PLCC32 socket adapter for it. This would allow you to reflash manually if your Xbox won't boot.

Then... download a pre-built XBOverlock executable from here: https://github.com/WulfyStylez/XBOverclock/releases and extract it to a folder, have the folder Explorer window open.

You will need a copy of the BIOS to patch for overclocking. Be it INDBIOS, Xecuter, etc. Anyway, you need the .bin file for this, and to put it in the same folder as XBOverclock. Note the filename. Open a command line window and get to the folder XBOverlock is in. The easiest way to do this to copy and paste the address from the Explorer window you have open by typing cd and then paste the folder address. You may need to put inverted quotes around it " if it has spaces in it.

E.g. cd "C:\Users\Giant Robots\Desktop\XBOverclock"

From here type xboverclock and note the instructions it gives you. Or follow the below example where one has 'indbios.bin' as the original BIOS, and 'patched.bin' should be the output. FSB controls the front-side bus clock patch, NV controls the graphics chip clock patch.

E.g. xboverclock -fsb 141 -nv 242 -o patched.bin indbios.bin

The program will let you know what has been patched and the values rounded down.

When you are done, FTP the 'patched.bin' BIOS file onto your Xbox and flash it the way you normally would ON THE MODCHIP! The Xbox will shut down as usual after flashing. Turn it on and pray. If it works, try playing something that is tough on the graphics chip. A good example is to open XBMC and play a video upscaled to 1080i (enable 1080i in the system settings). If the Xbox does not freeze while playing this, then chances are you have a stable overclock. Note: I have found that sometimes an overclocked Xbox can no longer completely flash a new BIOS image and the progress bar will jam, with no option to retry. This is the second reason you should always do this with a modchip you can manually flash: bricking your onboard TSOP (minus the Xbox 1.6 which does not have one) is a nightmare to recover from. The last time I had this problem I had to desolder the whole TSOP with a hot air station,  solder it onto an adapter board, reflash it with a PIC programmer, then solder it back on the Xbox motherboard. This took me hours to do since it is hard to tell if all the pins are correctly connected. Plus, it is dead easy to lift the pads by accident, permanently rendering it impossible to boot from TSOP! You should only flash there if you are *absolutely* certain you have a stable overclock, and do not plan to write another BIOS again. To do that of course you would need to disconnect your modchip and disconnect any wire you have between GROUND and the D0 point on the motherboard, then boot normally, and flash normally.

If, on the other hand, you cannot get the Xbox to boot normally (either black screen or a frozen flubber animation) then you will need to reflash your modchip externally as I have described above. A MiniPro TL866II and a PLCC32 adapter is a good candidate to do this. If you need help doing this part, give a word here and I'll post instructions in another post... this one is getting a bit long. Try again with lower overclock values and keep trying gently.

Edited by samspin
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