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Old 11-18-06, 01:05 PM   #1
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Join Date: Dec 2005
Posts: 6
Question do mtrrs matter anymore?

Can anyone tell me how much MTRRs matter these days?

I remember back in the PCI and AGP days, it was important to enable write-combining on the framebuffer region using MTRRs to get the best performance. Then, when the X server figured out how to set MTRRs itself, everyone was happy.

Now I've progressed to Linux on x86-64 with a PCI-E GeForce 6500, and it's just swell. But the X server doesn't set any MTRRs automatically (yes, they're enabled in the kernel and I can configure them manually). It's Ubuntu 7.1.1 (edgy) on a 2.6.18 kernel, if that matters.

Is this expected? Or rather, would it help performance if I configured MTRRs myself?

Thx for any advice. I'm not suffering from performance problems or anything, but I'm just curious.
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