Intel Raptor Lake 0x129 CPU Microcode Performance Impact on Linux

https://www.phoronix.com/review/intel-raptor-lake-0x129

by dangle1 • 2 years ago

40 9 2 years ago

debo_• 2 years ago

On a geo mean basis for 188 benchmarks run, the performance overall was flat from this new BIOS / CPU microcode... For the most part the performance was the same but there were some exceptions observed...

0x000xca0xfe• 2 years ago

Data movement/branch intensive code seems to be affected most (WireGuard -10%, some Python benchmarks -8%).

BearOso2• 2 years ago

The branching and the scripting language hit was unexpected. It slows single-threaded programs the most. That means this definitely wasn't caused by an out-of-spec high power limit set on the motherboards. So the common theory was wrong.

Games seem to be unaffected. There was suspicion regarding the timing of this patch and AMD's new processors coming out. That now seems to be unfounded, with only a minimal effect on consumer applications.

PaulKeeble2• 2 years ago

I have seen a bigger hit on my 13700k on an MSI Z790 board. About 2% on single threaded workloads due to the boost now not going past 5.3Ghz but 20% on multithreaded like Cinebench. The performance hit is really quite significant.

Its made even worse by the fact the pre microcode benchmark was on a hand application of Intels Default power recommendations to reduce damage, so 125W and limitations on amps and boost times. Its now running on performance mode which can use 250W. I don't understand how some people see no difference, others seeing a little and I am seeing a lot. Something is going on here.

Firerouge• 2 years ago

Perhaps by increasing the power limit to 250W you're also experiencing some thermal throttling now as well if the cooler can't burst fast enough or keep up with that higher wattage.

PaulKeeble2• 2 years ago

Its not getting above 75C its being cooled by a 360mm radiator. No thermal throttling at all.

sirn• 2 years ago

Do you know which BIOS/microcode you were running before updating to 0x129? Multicore workload should never hit anywhere near 1.55V which is the cap from 0x129, and 13700K should be capable of doing 5.4GHz at 1.3V even with the worst bin, so it's a bit strange to see this 20% performance hit on CB.

If this is compared to <= 0x123 (before the introduction of "Intel Default Settings") then this drop may be attributed to low AC Load Line configuration in previous configuration, which essentially undervolting the CPU out-of-the-box. >= 0x125 BIOS usually bumped this up/lower this down to Intel's recommendation. It could be very possible that AC_LL is setting too high on the MSI board after the fix.

It's still very strange though, even if AC_LL is the culprit, that 253W is running 20% slower than 125W. For what it's worth, I have two systems running 13900K and 13700K both with ASRock board, and I see no difference in MT performance with 1-2% drop in ST (though 13700K is running with PL1=PL2=125W, but that shouldn't affect ST).

Intel Raptor Lake 0x129 CPU Microcode Performance Impact on Linux

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