PPD from 8800GT

sir-les-mp · 2 Dec 2010 at 22:02

Ok im now officially bemused :confused:

Ive just reset this system up with a 9800 GX2 and 2 x 8800GT's
Now my understanding is with them all using the G92 core they should produce very similar PPD.
However the 2 x 8800GT's seem to be quite abit behind in the PPD stakes compared to the two 9800 GX2 core's.
For instance at present 1 of the 9800 GX2 cores is running a 783 with an approx PPD of 5500.
Both the 8800 GT's are also running 783 WU's and their PPd is 3242 and 3075.
Im not to worried about the difference between the two 8800's as one is clocked lower than the other.
However the faster of the 2 is clocked to the same as the 9800GX2 650/1750/1000.
So as i see it, it should be seeing approximatly the same PPD as the 98800 GX2.
I know the GX2 has 16 more shaders per core than the 8800GT but that should not equate to a PPD drop of over 2000 PPD for the same series of WU.

Or am i being a N00b and missing something plainly obvious

Frozennova · 2 Dec 2010 at 22:38

Somethings amiss, my 8800GT with stock clocks is pulling 4.3k on a 587 pointer

sir-les-mp · 2 Dec 2010 at 23:03

Im just wondering if its something to do with Windows XP Pro 32bit
When i was using these cards in my other system they all seemed to run properly.
The other system is running Win 7 Ultimate 64bit and a similar Motherboard.
This is all on the Asus M3A79-T Deluxe where as the other is the Asus MA32-MVP deluxe.
The only real difference is the newer board runs the SB750 chipset where as the other is the SB600 Chipset.
They both have the same amount of PCI-E lanes and Slots for upto Quad Crosfire

sir-les-mp · 3 Dec 2010 at 00:58

Well ive done a bit of tinkering
basically swapping the cards positions within the system but they still seem to be running as they were before.
There are 2 diffrences though ive managed to clock all cards to the same
and the 9800 GX2 is runninng slightly quieter as it seems to be getting more air from the side fan of the case and running at only 85% fan speed

Rroff · 3 Dec 2010 at 01:11

Could be down to drivers? nVidia have said that performance increases in newer drivers will concentrate on Windows 7 first and may or may not make it down to older OS - not sure how much that affects GPGPU tho.

Frozennova · 3 Dec 2010 at 08:11

Good shout on drivers Rroff, try dropping back a few versions of drivers as some of the newer ones seem to harm performance.

Im currently on 258.96

sir-les-mp · 3 Dec 2010 at 09:42

frozennova said:
Good shout on drivers Rroff, try dropping back a few versions of drivers as some of the newer ones seem to harm performance.

Im currently on 258.96

That is also the current drivers im using.

sir-les-mp · 3 Dec 2010 at 11:41

Ok an update
Ive just recieved an 8800GTS 512Mb from Miniyazz this morning
Just like the 9800 GX2 it has 128 shaders and it has been clocked to the same speed
It is reporting the same or similar PPD to the 9800GX2, the remaining 8800Gt in the system is still reporting a PPD of almost 2200 PPD less than the rest of the cards

Happy · 3 Dec 2010 at 14:01

sir-les-mp said:
Ok an update
Ive just recieved an 8800GTS 512Mb from Miniyazz this morning
Just like the 9800 GX2 it has 128 shaders and it has been clocked to the same speed
It is reporting the same or similar PPD to the 9800GX2, the remaining 8800Gt in the system is still reporting a PPD of almost 2200 PPD less than the rest of the cards

This is an issue when folding on mismatched cards with a different number of shader cores. I have experienced it before, and I know others have mentioned it on the forums. There's nothing you can do!

Edit, see here, some discussion of it:-

http://forums.overclockers.co.uk/showthread.php?t=18019091&highlight=username_Happy

didgemaster · 3 Dec 2010 at 19:18

GPU2 or 3?

from memory you can push card to 700/1782 core/shader

should be at 5000+ at least - try folding with one card to see what happens, I have not used different mismatched cards so Happy probably knows better