Conundrum of 3870 > 4850

[Particle]

So here's a good one. The following is an interesting and bizarre tale. I'd like to get some speculation on this:

Ever since I moved to my dual Istanbul rig, I've suffered from decreased graphics performance. It seems simple enough, right? I went from a 3.5GHz clock speed to a 2.2GHz clock speed. I'm still using the same Radeon 4850, but performance is in the gutter for some games.

Red Faction Guerrilla is unplayable at literally 2-3fps. I can count frames easily.
ArmA II is unplayable at about 5-8fps. I can't count frames, but neither can I aim.
Other games like all HL2 engine and UT3 engine ones play great. They're just a linear decrease from my old CPU clock speed.

An interesting point is that changing detail levels and resolutions seemingly has no impact on framerates at this point.


BUT


I swapped my Radeon 4850 for a Radeon 3870 I used to use so that I could put the 4850 in a sort of 'gaming rig'. Immediately, performance increased. In TF2 for instance, I went from a solid 20-24fps to a pretty bouncy 15-35fps. It feels better.

So the question is why. The 3870 has 320 shaders to the 4850's 800. Interestingly, I've noted that the 3870 has faster memory and a higher clock speed for virtually the same shader design. I wonder if the decreased CPU performance (since renderers and the ATI drivers don't exactly use multithreading effectively) drives fewer shaders better. I'm not sure on what level the hardware is exposed to the driver, but I certainly see it as a possibility.

These results are odd since generally the 3870 appears to only be about 50-65% as fast as a 4850 in reviews. I wonder why this system is getting +50 to +100% with it.

http://www.pcrpg.org/pics/computer/gpuz3870.png http://www.pcrpg.org/pics/computer/gpuz4850.jpg

[KoHaN69]

Driver issue.

[Particle]

Driver issue.

It's quite clearly not. I've had the same performance issue over about three installs of Windows (Vista, Server 2008, and Server 2008 R2) with various versions of Catalyst.

[G0ldBr1ck]

unless your 4850 has a problem of its own (have you tried it in another PC?), it almost has to be a driver issue with the platform you are using.

[swaaye]

Could also be some sort of mobo incompatibility with the 4850, or some sort of issue with that 4850.

[SocketMan]

CAT 9.8 VS CAT 9.9 ?
You can down clock your 3870 to the 4850's clocks and see what happens?

As far as arma2 goes maybe you need to specify the cpu#
That's my shortcut just in case:

"C:\Program Files\Bohemia Interactive\ArmA 2\arma2.exe" -nosplash -cpucount=4 -maxmem=4096


You'd need 12 for the -cpucount= of course.

Make sure you have the 1.4 patch installed (anything under 1.3 is virtually unplayable@high settings) and check the value for the view distance -
the higher the value the more cpu juice/cores the game wants.:)

[Particle]

CAT 9.8 VS CAT 9.9 ?
You can down clock your 3870 to the 4850's clocks and see what happens?

As far as arma2 goes maybe you need to specify the cpu#
That's my shortcut just in case:

"C:\Program Files\Bohemia Interactive\ArmA 2\arma2.exe" -nosplash -cpucount=4 -maxmem=4096


You'd need 12 for the -cpucount= of course.

Make sure you have the 1.4 patch installed (anything under 1.3 is virtually unplayable@high settings) and check the value for the view distance -
the higher the value the more cpu juice/cores the game wants.:)

The screen shots were just for reference. The machine I put the 4850 into was running 9.8. I tried both the 4850 and 3870 in my main machine running the same driver version (9.9).

I'll have to give that a shot regarding ArmA II.

[largon]

I'd say your 4850 is stuck at 2D clocks, or it is broken.
Leave GPU-Z running in the background with the option "continue refreshing..." ticked in Sensors tab and run some games. See if the clocks change.