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Strange 3870 performance issue?

fizzy

fizzy

fizzy

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Joined
16 Jan 2003
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1,236
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by my pc. :D
Hi,

Been sorting out my crossfire setup giving a spring clean and refit, and I'm having some odd quirks with performance.

Systems is Asus A8R32-MVP, AMD X2 socket 939 @ 2.75ghz, 4 GB memory (DDR), currently using XP32 (XP64 was having issues with HDDVD/Bluray player support etc). Using 2 x 3870XT 512MB with both crossfire links in place. Using 8.6 drivers.

Ran 3dMark 06 and there is a difference (albeit small) between crossfire being on and being off (9300-odd vs 10400-odd) so looks like crossfire is in fact engaging. SM3.0 figure went from 4000-ish to 5500-ish.

Using fraps, did a playback of a demo I recorded earlier on UT3. No crossfire - min 45, max 380, avg 67. Crossfire enabled - an extra frame or two increase on minumum, but thats it??? In fact max frames dropped a bit? :eek: This is at 1920x1600, all settings on max with no vsync.

Tried Bioshock, saved game at opening section when floating in the water (first time you have manual control). Fraps showing 35 fps with no crossfire.....and .... 35 with it enabled? Again, same res with all settings on max, no vsync.

Next - the witcher. When in village/outdoor section in chapter one, generally doing 25 fps without crossfire - and again the same with it enabled? Max settings, no vsync etc. I even dropped the AA and AF settings way down and it had little effect on the frame rates...

...rather confused now. Whats causing this? I realise that the cpu may be holding things back but surely maxing out the AA/AF should show if this is a gpu or cpu limit.

Is there any GPU heavy benchmark apps/games I can use to see if any tweaks have an impact on base performance?

Was considering removing the two 3870's and fitting a single 4870, but I'm assuming that if my system is not coping with what it has it won't be any better with the 4870.

Hopeing its something simple - don't really want to have to splash out on a new crossfire board, cpu and DDR2/3 mem.

Any ideas?
 
Maybe worth a reinstalling 8.5 cats ? I noticed my own single 3870 taking 300 point loss in 3dm06 using 8.6 cats which ive had no luck recovering apart from going back to 8.5. no noticable loss in games, but no gains either. Maybe worth checking out to see if they broke 3870 support ready for 4970 just to make the new cards look better :D

http://service.futuremark.com/compare?3dm06=6940358 This is my last 3dmark06 score on similar motherboard your using if its of any use.
 
Last edited:
This is getting wierder... ?

On HalfLife - Episode 2, I made myself a demo in the section were you are defending from an ant lion attck from various tunnels...

Was getting 65fps on max settings with no CX. Enabled CX - got same fps? Rebooted pc - tried again - then got 100 fps! Woohoo! Looks like something is stopping me switching "on the fly" or something?

Still no difference in the witcher though.

Saw a mention of a Devil May Cry benchmark, which I downloaded.

Ran it at 1920x1600, all max settings. Got 50 fps, 33 fps, 63 fps and 40 fps with a rating of "C" with CX enabled. Ran again with CX disabled - got same figures??

Ran with no CX, but no AA - got 72, 46, 100 and 63 with a rating of "B"...??? Thats faster than my CX setup (but not using AA). So enabled CX with no AA, and got - 128, 90, 147 and 77 with a rating of "S"??????

Just to make sure, selected 8AA again and reran benchmark - got same figures as original test.

Either there is a serious issue with my setup somewhere or AA is not only bad on 3870's, there's no improvement using a second card when using AA? HL2 has AA setup in max settings though doesn't it?

Tried using the GRID demo, but with CX enabled it just caused wierd flickering loading up then it hangs when loading the menu. :(

All very strange. May look into selling my 3870's and getting a 4870 instead - as that should be around twice the performance of a 3870 anyway? I'm also assuming that if the 3870 works with my board then the 4870 will as the both require at least pcie 1.1?
 
MinDBlanK said:
Yip, It'll work, would be good if you had a psu with 2 PCI-E connectors. 6 and 8 pin. (I think!), Great help me!
Click to expand...

I'm using two 3870's, so yes I have two pcie power connectors... :D Its a corsair psu which has the 8 pin ones as well.
 
MinDBlanK said:
Have a read of this for setting up your drivers correctly.

http://www.tweakguides.com/ATICAT_1.html
Click to expand...

Thanks - some usefull info in there. I've just done a fresh install of XP (it needed it) and optimised xp performance - always tend to remove anything unwanted/unrequired anyway, tweak settings etc.

My CCC settings are at default with pretty much every 3d option in "set by application", AI on (recommended for CX I understand?) and CX on obviously. The only thing I could see that may help in the article is a couple of options in the gaming profiles 3D sections, but apparantly that will only gain a couple of fps at best.

Still not sure why there is such a difference in various test results in games, almost as if the CX is working intermittantly... was even suspecting a card problem at one point.

I have both link cables in place too, and Gpuz states CX is active.
 
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