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512Mb 9800GT big performance drop after trying 1Gb version


basshead
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I've been using a 512Mb 9800GT with a Gigabyte Z68XP-UD3 and i5-2500k running 10.7.3 with good performance for what I do. I picked up a cheap 1Gb version of the card recently, so shut down the hackintosh to swap them over to see how much difference the extra memory made. After rebooting and running some benchmarks I swapped the cards back, as the stock cooler on the 1Gb card was very noisy compared to my Artic Cooling replacement on the 512Gb card.

Performance using the 512Mb 9800GT has now dropped noticably, and simple things like moving between spaces/desktops has become jerky. I downloaded and ran Luxmark 2 and got a score of 7 instead of the suggested 78 for video card alone.

I set Graphics Enabler to No and restarted, then enabled it again but that had no effect. I'm wondering if Lion is now crippled by expecting to see 1Gb of video ram, is there any way to reset Graphics Enabler or Lion's Video system?

 

any help or suggestions would be much appreciated.

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  • 2 weeks later...

I had a similar problem and I can never remember what to fix after every point release. Well, finally I got my act together and tracked it down. I hope writing this will commit it to my memory better.

 

The problem is with /S/L/E/AppleGraphicsPowerManagement.kext. It's improperly calibrated for the card and gets reinstalled in pretty much every OS X update. You have two options:

 

1) Rename or move the kext and rebuild your caches.

2) Change your smbios.plist to use MacPro3,1 which apparently doesn't use the kext.

 

I think #1 is an easier approach that will mess with less.

 

Enjoy your silky smooth video.

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Yep could be the AGPM problem (there is an Nvidia AGPM thread available here) OR the crad itself.

The speed may vary by GPU max. MHz and also VRAM Speed in MHz. Some 1 GB versions , for marketing, use bigger but much slower VRAM = much less overall speed. Like simple less VRAM Mhz or even more bad using DDR2 insted of DDR3.

You could also compare both cards by Galaxies (openCL bench) there are already some similar gpu type results listed.

Really bench both, then you see diff or not. Normaly non working AGPM gives 1/2 of the speed of working AGPM, not much less.

http://www.insanelymac.com/forum/index.php?showtopic=276190

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