optimized client benchmark results while OC

[mitchellds]

Greetings all,

I noticed that after running the boinc benchmarks after overclocking my amdx2 4400 I actually get worse Dhrystone results. My original results at the default settings were:
2137 Whets
3966 Dhry's

after Oc'ing and bumping up the speed by 200mhz I actually get the below results: notice that the dhry's are down by 1789 but the whetstones are up.

2309 whets
2177 Dhry's

Any ideas why this would be? Are the Dhrystone measurements actually affected by that much by oc'ing, or could the boinc client be reporting incorrect results?

I have a Av8pro with 2 gb of ddr 400 corsair memory, and am running the optimized boinc client posted from this site.

[NeoGen]

That's an odd one...

Have you tested the stability after overclocking? Maybe instabilities can lead to glitches on the benchmark...?

By the way... those values seem kinda low. Are you using the boinc benchmark or some other? Look at my boinc benchmarks from an AthlonXP 2000+.

Measured floating point speed 1619.2 million ops/sec
Measured integer speed 4496.03 million ops/sec

[drezha]

Looks like a BOINC benchmarek but not using an optimised client. ;)

[mitro]

Either force the computer to run the benchmark again (sometimes I get unusually low ones) or the OC isn't stable enough to even handle the benchmark let alone the work. Whatever it is, somethings definately wrong... depending on the client you should be getting much higher benches.

[NVM]

i just checked my Opteron 165, running stock speeds with optimization.

Measured floating point speed 8578 million ops/sec
Measured integer speed 6040.88 million ops/sec

[Strongbow]

I'm no OC'ing expert, Mitro's our guru in that area, but it sounds like the following.

Whetstone is the floating point benchmark so if you speed up your processor then this will be affected.

Dhrystone is the integer benchmark so if you speed up your memory and sysboard (along with processor) then it will increase as it counts the number of loops the test does.

So it sounds like there is a bottleneck probably due to the processor storming along but then hitting contention in the cache due to having to wait for it to read from memory before continuining the next loop. I would suggest checking your memory and sysboard settings to see if they can be aligned with the performance of your stepped up processor.

Could be completely wrong but worth a check!

Mitro needs to step in here to add some experience!

[AMD-USR_JL]

My drystone goes down a lot too if i oc it too much. Try lowering the base frequency a little, it should help.

[Lagu]

Hi

I have over clocked my computer from 2247/204 MHz to 2310/210 MHz and have this benchmarking result:

2006-04-27 14:37:04|| 3092 double precision MIPS (Whetstone) per CPU
2006-04-27 14:37:04|| 9437 integer MIPS (Dhrystone) per CPU

Lagu

[mitro]

Mitro needs to step in here to add some experience!

Well you asked for it. :D

First of all, people are throwing around 2 different pairs of numbers (or atleast with my client its different). The Whetstone/Dhrystone scores are what are shown if you look in the messages tab of BOINC, while what is listed on the project websites under you computer details is reported as floating point/integer speed (why its different I have no idea).

Now... blackheath, I have to dispute something posted. Memory speed has literally nothing to do with either the Whet or the Drhy. :P

I ran the benchmark twice here at work on my Opteron 175 (OCed to 2640 MHz). The first time I was running 240MHzx11 with the memory running 1:1 and got:

2693 Whetstone
9119 Dhrystone

(This is using the truX calibrating client, by the way)

Then I changed the memory divider to 5:6 (making the memory run at ~200MHz) and got:

2686 Whetstone
9139 Dhrystone

So 40 less MHz on the RAM and the difference was definately not enough to conclude that memory speed (and therefore bandwidth) has any affect on the scores.

Like I said originally, I get those low benches occasionly and I just force it to run again. I use BoincView so I can see if my credits/hour is lower than it usually is.

OT: Opteron 165 coming later today, so I'll have to post tonight or tomorrow just exactly how I OC it.

[Strongbow]

Now... blackheath, I have to dispute something posted. Memory speed has literally nothing to do with either the Whet or the Drhy.

You are sort of right Mitro my friend :D , Whetstone is strictly just CPU but Dhrystone is an application that after a few cycles could partially sit in L1, L2 or L3 cache on the processor so it too would not be affected directly by memory performance- unless of course the caches get filled due to lack of coherency and have to wait for validation from main memory. This can often happen in large SMP systems due to bad coding but I'm sure it could happen to the smaller x86/x64 chips as well as they only use MESI protocols rather than MOESI or MOWESI (which my company is about to release in it's next generation of SPARC chips) so they have even less intelligence and would cause the processor to waste cycles during wait for validation. Many things could cause the lack of cache coherency of course and adjusting your sysboard and memory could have affect if there are numerous instructions being performed which are causing the processor to wait several cycles for an answer from main memory.

I must admit though, I'm coming at this from a SPARC background so the above could all be pants but I doubt it!