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Slow G5 nvidia 7800gt ??? (help)

MrVitalic

MrVitalic

macrumors regular
Original poster
Mar 16, 2020
164
205
Hello my dear ppc amateurs. Last year I bought a evga 7800 gtx ko 256mg with the idea of converting it to a powerpc gpu. I failed at modding a vbios then failed when doing a bad flash ( eeprom was too small, bad rom). So today, almost a year after, I decided to convert the card to a 7800gt for powermac by:

1: flashing a 7800gt rom from the macelite onto a macpro 7300gt
2: desoldering the eeprom from the 7300 and soldering it to the 7800gtx

Everything work, I have a boot screen, the card is shown as a 7800gt but the card lack performance. My 6600le is twice as fast in everything I tested so far (the 6600le is faster in classic itune visualizer, twice the fps in quake 4 (30fps vs 15fps), a bit higher score in xbench (160 vs 130)

Did I missed something ? I thought these cards where the top tier for pcie G5. I understand I modded a gtx into a gt but to my understanding they run the same nvidia G70 processor (as in saying a gtx is a gt with higher clock speed).

Picture are there to show the whole process (for your enjoyment :p) THX!!!

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IMG_3303.JPG

IMG_3308.PNG

IMG_3309.JPG

IMG_3312.JPG

IMG_3314.JPG

[automerge]1586756144[/automerge]
I just noticed : From a fresh boot, the fan spin, but when initialized by osx it stop and never spin again. So the card is basically cooking itself running a 68c (but some gpu run hot). I presume the card is down clocking itself.
 
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I found out my card got 4 fan wire and the original mac gt have two. I'l solder wire on the header tommorow to test if theres any voltage passing in when the card is booted (maybe it can be a quick fix)
51HCSYtbKAL._AC_.jpg




I'v removed the plastic header for the plug.

IMG_3315.JPG
 
You could even buy an extension with adapter and connect it to the motherboard.
Who needs fan control anyways? ;)
You just run it at 5V or 7V always. I think it would be better.
 
philgxxd said:
You could even buy an extension with adapter and connect it to the motherboard.
Who needs fan control anyways? ;)
You just run it at 5V or 7V always. I think it would be better.
Click to expand...

:p I didnt posted a picture of the card installed. I tried different things... Theres now a 3 pin fan plugged running on 12v (5 or 7, didnt check). I found out the card work the same (very slow) with and without the additional 6 pin power plug. Last thing I’l try with this rom is using an external psu. If it doest work, this mean a gt rom cant work on a gtx.

In this post (https://forums.macrumors.com/threads/7800-gtx-rom.1552556/page-2)
Someone mentioned the idea of trying the custom rom for a gtx 512mg on a 256mg. I’l try but I’m sure the card will crash when paging more than 256mg. At least if the 512mg rom work (speed), I’l try again to edit the timing table ( its very confusing editing little endian and big endian code. I should try a different editor)
 
Purely for reference purposes, here is my flashed 9700 Pro and X1900 GT:

Picture 1.png

Picture 2.png


There definitely might be something amiss with your 7800s.
 
Or this test is crap.

I think Doom 3 or Quake 4 is a better indicator for performance.
What did you get in Open Mark?

Bild 2.png

Bild 3.png
 
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A chance to make a Doom3 timedemo?

Doom can be found in the Macintoshgarden (updated to 1.3.1)
add set com_allowConsole "1" to DoomConfig.cfg (under ~/Aplication Support/Doom 3)

CTRL-ALT-[~] (to open Console)

timedemo demo1

Graphic Settings Medium (640x480)

Bild 5.png


Or did you have other Benchmark results?
[automerge]1586885453[/automerge]

Or OGL Extension Viewer?
Bild 6.png
 
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@TzunamiOSX @z970mp Thx both, I really appreciate. I’l do some benchmark tonight if I dont fall asleep when I get back from work.

I ordered a ch341a programmer from amazon yesterday (1 month shipping ehh) to help me mess with the rom. I was suppose to get it by tommorow tho. Friday I’l try to hard wire my rapsberry pi to the eeprom to flash a gtx rom on it (using flashrom).

I did an impulse buy on a radeon x1900 gt advertised for G5/mac pro but I think its a x1950 xt 256mg or at worst a 512mg card. Anyway, I hope betwwen the two I can make myself a proper pcie G5 gpu. Have a nice day!
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TzunamiOSX said:
Are you using a modified Leopard?

i'll get this with a Radeon 9800
View attachment 905853
Click to expand...


No I dont use a modded leopard (10.5.8 fully updated)
 
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TzunamiOSX said:
Or this test is crap.

I think Doom 3 or Quake 4 is a better indicator for performance.
What did you get in Open Mark?

View attachment 905843
View attachment 905844
Click to expand...


Heres my openmark result for the 7800gtx flashed to a gt
Picture 1.png

Picture 2.png

Picture 3.png



and here is the result for my nvidia 6600

Picture 5.png


Obviously theres something wrong. I tested the 6 pin power connector and it provide 12v on each 3 pins. I'l go back to the drawing board. I'l first try the 7800gtx 512mg rom ( found on marumors) then try to modify the timing table to fit my 256mg card.

*Note that I'm on slot 3 because my 6600 is in slot 1 (running in x8 dont affect the score)
 
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these are very low resuts

First, remove the 7800 and look for a sticker with the Firmware version. On a 7800GS you have a limitation

The BIOS Revision number indicates the GPU model used on the card. 5.70.xxx.xxx means the card has G70 GPU - original GeForce 7800 GPU. Newer cards use the same PCB but a different GPU - G71 which is original GeForce 7900 GPU (BIOS Revision number is 5.71.xxx.xxx). The card's commercial name still remains GeForce 7800 GS but these newer cards are actually GeForce 7900. NVIDIA had to rethink the ROM CODE structure for G71 and newer GPU, that's why it would need a very different MAC ROM to work.
Click to expand...

Perhaps this is the same at GTX

Second, check performace with only one GPU installed

z970mp said:
Purely for reference purposes, here is my flashed 9700 Pro and X1900 GT:

View attachment 905835
View attachment 905836

There definitely might be something amiss with your 7800s.
Click to expand...

not really, looks like there is somthing better with your System or GPU.
[automerge]1587042822[/automerge]

@MrVitalic

Im confused, is it a GT or GTX

Did you flashed a GT rom to a GTX GPU?
 
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TzunamiOSX said:
not really, looks like there is somthing better with your System or GPU.
Click to expand...

Precisely.

I suppose that being a very powerful card, the X1900 could legitimately win. However, I don't think a 9700 Pro is supposed to largely outperform a 7800 GS. It seems that the 7800 only bested the 9700 in Quartz Text.

Perhaps this is a kext problem and OS X can't take full advantage of this card because of it?

As I was telling @Dronecatcher, there is something called glmark2 on Linux. That may reap different results, providing this is a software issue as proposed.
 
z970mp said:
Precisely.

I suppose that being a very powerful card, the X1900 could legitimately win. However, I don't think a 9700 Pro is supposed to largely outperform a 7800 GS. It seems that the 7800 only bested the 9700 in Quartz Text.
Click to expand...

Look at my Radeon 9800 this card is also slower than your Radeon 9700. Did you modifiy your MacOS? 10.5Trim or something of your stuff^^?
 
TzunamiOSX said:
Look at my Radeon 9800 this card is also slower than your Radeon 9700. Did you modifiy your MacOS? 10.5Trim or something of your stuff^^?
Click to expand...

Yes. The Leopard install I ran that on was optimized with AuroraTrimcelerator, Monolingual, and maybe ShadowKiller.
 
z970mp said:
Yes. The Leopard install I ran that on was optimized with AuroraTrimcelerator, Monolingual, and maybe ShadowKiller.
Click to expand...

I think, this is the reason why your values are higher. Is it possible to test your GPU on a normal Leopard?

@MrVitalic
If you really patched a GT ROM to a GTX is this the problem. Lower clock speed and deactivated parts of the GPU.

Here, but with no warranty


forums.macrumors.com

7800 gtx rom

I have posted the ROM to the 7800 GTX as an attachment. HAPPY FLASHING :apple:
forums.macrumors.com forums.macrumors.com
 
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TzunamiOSX said:
I think, this is the reason why your values are higher. Is it possible to test your GPU on a normal Leopard?
Click to expand...

No OSX tweak will make a significant difference to GPU benchmarks.
I noticed that the quoted OpenMark scores in the thread aren't scores but various FPS points - check thread here for how scores are registered.
 
TzunamiOSX said:
I think, this is the reason why your values are higher. Is it possible to test your GPU on a normal Leopard?

@MrVitalic
If you really patched a GT ROM to a GTX is this the problem. Lower clock speed and deactivated parts of the GPU.

Here, but with no warranty


forums.macrumors.com

7800 gtx rom

I have posted the ROM to the 7800 GTX as an attachment. HAPPY FLASHING :apple:
forums.macrumors.com forums.macrumors.com
Click to expand...


Yes this was mentioned in my fist post. I was fool enough to think I could convert a gtx into a gt ( same G70 gpu afaik). I'l try as soon as possible the gtx rom. I just have to figure how to flash a fcode bios with nvflash (the bios is now unrecognized). Either I wait for my eeprom programmer to get to my door or I hard wire my raspberry pi and use flashrom under raspbian. All my apologies for the misunderstanding. Thx for the help!
 
Try reinstalling with the 7800GT in. My MDD with a 7800GS was slow as hell, no better than the Radeon 9000 that was in there before. I thought it might be a driver issue and reinstalled the OS and it was much, much faster. I did also install Tiger instead of Leopard but if anything Leopard should have better support for these newer cards.
 
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