February 27th, 2003, 12:53
This was deviating from the original thread( so I started it over here in the FreeBSD Kernel section. 8)

Is there something that needs to be done for optimization for AMD CPUs? I noticed a drop of performance when switching to FreeBSD with my AthlonXP.

i believe there's a kernel option i might have this wrong i cant get into my box w/ the athlon at the moment.. but athlon_sse_hack

Here's the cpu portion of my dmesg on my 4.7-stable box.

[code:1:c100218a30]CPU: AMD Athlon(TM) XP1800+ (1560.35-MHz 686-class CPU)
Origin = "AuthenticAMD" Id = 0x662 Stepping = 2
AMD Features=0xc0400000<AMIE,DSP,3DNow!>[/code:1:c100218a30]

You can see SSE is in there so we add "options CPU_ENABLE_SSE " to the kernel. The athlon_sse_hack is for when your bios isn't enabling it. It's not needed if your bios is playing nice but it doesn't hurt to have it in there. Either way make sure and add the SSE option too. USER_LDT is needed by many multimedia apps so add that if you haven't already for Nvidia drivers.

I've seen conflicting thoughts on the CPU_FASTER_5X86_FPU option for an Athlon or AthlonXP. I guess a little benchmarking is in order.

February 28th, 2003, 00:38
I take it this is for motherboards that aren't recognized by the kernel also? I would figure this is why my box slowed down after the switch to FreeBSD, considering it's a chipset that Linux still doesn't even support (and probably never will).

February 28th, 2003, 12:10
What kind of motherboard you have in there?

Perhaps you can post your dmesg and any tweaks you've made from generic for the cpu and mb.

March 9th, 2003, 06:27
Looks like that did it I guess. B4, mplayer didn't complain about SSE, now it does. :D

As for mobo tweaks, never had to do any.....surprisingly. :P

March 9th, 2003, 06:43
Nevermind. Even with the extra instructions, I'm still running slow. Any ideas?