Comment 12 for bug 129172

Thanks, Amit.

Here's /proc/mtrr:
reg00: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
reg01: base=0x100000000 (4096MB), size=4096MB: write-back, count=1
reg02: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1
reg03: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1
reg04: base=0xdff00000 (3583MB), size= 1MB: write-through, count=1

In the meantime, I'd done a bit more testing, and found that this also affects the Mandriva and Gentoo installers/Live CDs. Therefore, I cross-filed it as a kernel bug (I hope that was the right thing to do): http://bugzilla.kernel.org/show_bug.cgi?id=8883
Interestingly, the performance is slow on Fedora core 7's x86 install CD, but fine on Knoppix 5.01 x86.

I've also asked Gigabyte tech support in case it's a BIOS bug; no reply as yet.
And yes, I do think it sounds quite similar to #132577.