Update on my FX-4100, MORE tuning/performance

[damric]

Back from the Mardi Gras parades, time for an update on my FX-4100.

A few weeks ago MSI sent me a new BIOS to try. Even with the new BIOS, I still couldn't boot with my memory on the 1866 divider.

I tried a few things like putting my memory in the other two slots (it's still there), didn't make a difference.

I figured since it looked like I was stuck at 1800MHZ memory, maybe I could further tighten timings.

That worked out pretty well. With some extra DRAM voltage (1.75v), I was able to hit CL7 1T stable. It didn't seem to scale performance wise though so I set it back to CL8.

I twiddled around with the sub timings in AMD Overdrive to save reboot time. Things were looking pretty futile.

What I hadn't tried since the BIOS update was to raise HT reference in AMD Overdrive. I wasn't expecting much, as my motherboard pretty much would refuse to boot anything over about 230 or crash in AMD Overdrive. But apparently not today.

240, no problem.250, still not crashing.260, pushed it too far. Will it work in BIOS? YES.

Now my stable 24/7 overclock (in BIOS):

HT reference: 250

CPU Multiplier: x18 = 4500MHZ

CPUNB Multiplier: x12 = 3000MHZ

RAM: x8 divider = 2000MHZ 8-10-9-28 1T

HT Link: x10 = 2500MHZ

My new MaxMem score:



After finding AMD's FX Tuning Guide buried in the corporate website, I've been experimenting with higher CPU clocks. It takes much more voltage for small gains, but the chip responds to the voltage quite well regardless. I have flirted with stabilizing 5.0 GHZ, but it looks like it will take more than 1.65volts. At this point, stress level temperatures are about 65'C with my fans at full blast and a cool room temperature. The chip definitely looks like it has more to give with some improved cooling. If fab improves, sucessor chips like piledriver should be even easier to overclock.

What really amazes me is the performance scaling above 4.5GHZ. CPU benchmarks score quite linearly, and even memory performance improves with a higher CPU clock.

AOD benchmark at 4500MHZ vs 5000MHZ (multiplier changed to 20):


Maxmem score increased at 5GHZ also:


I must say I'm now impressed with performance of this chip (at the 24/7 OC). Tuning the memory to 2000MHZ seemed to help it a bit, as I gained a few more minimum FPS in games. Average and maximum FPS were also gained, but I don't care so much about that as I usually game with V-synch on anyway.

Here are shots of performance scaling with memory at 1333, 1800, and 2000. I ran the CPU intensive "Action Scene" benchmark in Far Cry 2 and this is the results of 5 loops each.

1333 CL8


1800 CL8


2000 CL8


I dare say that real world performance now equals or exceeds my old overclocked Phenom II 955 rig. I think I spent about $160 on that chip, but I can't remember as that was a couple years ago now. I paid $120 for this chip, but it came with some free thermal grease and a $20 gift card, so effectively $95. I reckon the price to performance ratio is good. The only thing is that the Phenom II Zosma can still be found at around the same price. When those dry up, this will be the best AMD tweaker's chip for around $100. The fact that it's now working properly on my 890FX board is gravy.

[Inceptor]

Nice job.
But how much power does it eat at full load?

[damric]

Originally Posted by Inceptor

Nice job.
But how much power does it eat at full load?

Just judging from heat dissipation I would put it about the same an Athlon II x4, even at 4500MHZ. Heat sink is still pretty cool under stress

It's a different story once I was pumping voltage to get frequency beyond 4500MHZ. Again, just comparing to heat dissipation of chips I've owned in the past, I'd say that at 5GHZ it was eating as much power as my Thuban at 4.2GHZ