Performance question

[fizzy]

Hi,

Trying to determine which would be the best path for an upgrade - cpu or gpu.

Doing some testing, using the game I'm playing mostly at the moment - GRID.

Using 2 3870's, on an asus A8R32MVP, Amd X2 @ 2.7ghz, 2GB mem on XP.

Running grid on medium settings, 1920x1200, AA on "Level 1", vsync off.

On single card on above settings I'm getting reasonable fps in the menu screen (40), and in game its pretty constantly at 30 or so and quite playable.

Switched on crossfire, and the game gets worse?? 36 in menus and a huge drop in-game (struggles to get to 20+), which makes its pretty much unplayable. Checked with GPU-Z to confirm when the 2nd card is under load or not. In Crossfire mode, both cards appear to be pretty much maxing out?
The only place I see noticeable improvement is the loading screen 3D text sections where it's around 75% faster with CX enabled.

I'm confused - it seems to show a GPU limitation but why so much of a hit with crossfire on?

Have been using a few other games for testing (UT3, DMC4 etc) and came to conclusion that in most cases my cpu/board appears to be the bottleneck, and the card when I use a lot of MSAA, as expected.

Was planning to upgrade to an intel crossfire board/cpu but from testing GRID it looks like it has major issues with crossfire anyway.

Anybody else have wierd issues with GRID and crossfire? Perhaps I should get a 1GB 4870 when they come out instead....but I'll probably be majorly cpu limited too. Decisions decisions.....

Freshly re-installed XP, and using Cat 8.7 drivers.

 

[Snapshot]

Have you used Task Manager to see what the CPU is doing while the game is running? That should show you pretty quickly whether the CPU is the bottleneck or not.

 

[psychas]

well u should ditch 3870 and get 4870 wich will be much faster then two of them . maybe get 2 more gig of ram

and overclock cpu bit more if its possible

 

[fizzy]

Have you used Task Manager to see what the CPU is doing while the game is running? That should show you pretty quickly whether the CPU is the bottleneck or not.

Yup, I've done a lot of testing on various games to see at which point the cpu no longer become a bottleneck etc, using various resolutions and monitoring with GPuz, task manager and windows performance monitor logging.

Anybody aware of an application that shows both cards GPU temps and load at the same time? I have to switch between cards in GPUz and it clears the display each time I do.

For example, I had problems with performance on the witcher too, and I could see that one of the cores was being maxed out, but gpu's were not - bad multithreading there.

With GRID the cpu load is a lot more balanced and on both cores, but GPU's are maxed out according to GPUz.

 

[fizzy]

well u should ditch 3870 and get 4870 which will be much faster then two of them . maybe get 2 more gig of ram

and overclock cpu bit more if its possible

Yeah, considering getting a 4870 1GB as that should do very nicely for a 1920x1200 res. Crossfire is a bit too hit and miss for me at the moment - but then that could be as I have an early crossfire board and oldish processor.

I've managed to add in an additional 2GB, but as I'm using XP32 its showing the max available memory as 3GB, even with PAE and related bios settings enabled.

I was using XP64 but was finding issues with obtaining hardware drivers and the like - it seems to have been neglected in favour of Vista 64.

 

[LoadsaMoney]

Didn't you have to rename the .exe for CrossfireX to work in GRID or something.

 

[fizzy]

Didn't you have to rename the .exe for CrossfireX to work in GRID or something.

Tried that - renamed it to "fear.exe" - no effect. I believe they have ammended crossfire settings for GRID in the last driver set or two anyway. I used to get major corruption on screen/screens wouldn't load before if CX was enabled when playing the GRID demo.

I've checked and when CX is enabled when playing GRID both gpu's are nearly always maxed out - which would imply its trying to do something in crossfire, just it reduces performance a lot. I believe its simply because it's not been officially supported or utilised by the developers.

I've been tweaking bios settings, driver updates, resource allocation etc to help. CPU is pretty much at its limit and crashes if pushed any higher. Removed a few IRQ shares which has made things run a fair bit smoother, but no faster. I'm reaching the point now that in order to make the most of my screen I'm looking at replacing pretty much the whole pc.