IBT

[paradisiac]

i understand that the clock is going to be an indicator in speed, but you cant tell me my 4 core i5 2500k @ 4.8GHz would be the same speed as say a phenom X4 @ 4.8GHz? so there has to be more to it than just the clock speed

 

[paradisiac]

Normally yes, however SB supports AVX, effectively doubling the GFLOPS, as it can push 8 instructions through per cycle over the Phenom's 4. When AMD release AVX compatible chips they will be on par again.

so does that mean the 2600k with their HT will be pushing 16 instructions per cycle?

 

[paradisiac]

Sorry I meant "8 operations" above, changed now.

No, but I don't know enough about micro-architecture to explain why. Hyper threading utilises more of the cores so should move the GFLOP measure closer to the max. However the chip is still only able to do 8 FLOP per core per cycle.

This should all be checked by an expert, this is just my thinking about it as we go along.

lol ok. i dont actually understand it all, far too complicated. but now i have done my IBT run (124.*** Gflop/sec @4.8GHz ) then i can run a few apps like media converter and see if there is actually any increase in performance or infact any instability IBT missed

 

[paradisiac]

well its done 2 hours prime testing too

 

[paradisiac]

The biggest problem I had with IBT is TIME! I have 8GB of RAM and it takes 120s to do one run! (on max)

Bugger doing 35+ runs

i did 50 runs, at 131ish secs per run and took around 2hours. prime is a minimum recommended of 8hour test, so do the maths

 

[paradisiac]

ok, well it did the 50 runs of IBT fine, a good 5hours+ of prime, loads of benchmarks and ran ok for general browsing, office etc. 5mins into crysis and BAM!!!! locked up.

 

[paradisiac]

Graphics card?

Seriously that's pretty surprising.

dropped back to 4.6GHz and crysis ran for well over 2hours so i would say that it just wasnt quite stable @ 4.8GHz.
im not too bothered as i didnt spend a lot of time tweaking the oc so its probably something i overlooked.

 

[paradisiac]

It's 'par for the course' Joeyjojo when pushing for the maximum clock from a CPU.

Not everytime, granted, but enough not to class a CPU stable untill it's run for a few days/weeks with normal usage without a BSOD.

You don't experience it so much with moderate clocks - but when pushing a CPU to its limit - then stress testing alone will not always find all a clock's weaknesses.

As mentioned previously some CPUs can pass all stress tests you throw at them and then 'trip over' with day to day usage.

I know it's hard to comprehend - especially when it's passed 20 runs of IBT (50 in this case) and 24 hrs of prime etc - only to then BSOD with light apps use. It can be infuriating...

However, if you look at 'day to day' usage as the final stress test - it's not so dissapointing when it happens.


@ Parasidic - 4.GHz is a great clock and you may yet be able to tweak 4.8GHz.

im 99% sure if i upped the vcore to 1.4-1.41 it would be stable, and probably go up to 5GHz, but i dont want to take that chance.
4.6GHz is good enough for me, so will fiddle with that to get the lowest 'stable' vcore and temps at that

 

[paradisiac]

Thanks Plec, you may well be right.



I find this far more likely though. I don't believe it's possible a system will pass IBT, then BSOD at idle/day to day usage.

Our friend has in his sig "700w Modular PSU". It's probably a no name brand and can't provide the amps.

yeh its an evolabs so might well be the case but it seems ok at 4.6GHz so it will stay there until i get problems. i will eventually upgrade my PSU when the new batch of gfx cards come out.

 

[paradisiac]

not sure if thats good enough to read.

 

[paradisiac]

P.S. Nice rig

cheers, looks nicer with the gfx cards fitted
have to strip it back down on sun/tues to work out my slow boot issue.

 

[paradisiac]

i was playing crysis not crysis 2, but i cant say i noticed anything getting louder, but then on the whole with all the fans its pretty loud to start with.

but..........

the air is sucked in from outside the case (fan on bottom of psu) and out the back, so no internal air should pass through the psu.

 

[paradisiac]

Bit tech says those cards pull 230W each. If the chips doing 160 that's 620W, which is getting close to max.

This says each card pulls 10.2 amps. If they're overclocked it could be higher. Seems reasonable to assume you need a beefier PSU.

under full load my british gas wattage reader thingy says my psu uses around 500-600w so i suppose that is very close.
i could swap it out for the 800w model, but will that not still have the same ampage?

 

[paradisiac]

its a modular psu, so obvs everything has its own rail on the outside of the psu, but im not sure what goes on inside the unit

 

[paradisiac]

it would have to be the 800w version of what i have (although on that one it now states its a revised model with i1/i7 support) until nearer xmas when i do my next big upgrade.

 

[paradisiac]

No, different external connectors can go on the same rail internally. One needs to see the connection diagram that usually comes with the documentation.

evolabs appear to not come with any of this

 

[paradisiac]

that makes sense. so would the

EVO-800W-MOD
Key Features:

•Type: Evo Labs 800W Modular High Efficiency
•Modular PSU: Ez Connectors
•Multi-GPU support: independent double +12V rails designed specially for dual graphic cards
•AMD support: supports the newest Athlon 64 CPU by AMD
•Intel support: supports the newest Core i5 & i7 CPU by Intel
•Active PFC: enhances utilization of energy
•Ventilation: 1 x 14cm fan
•Full range: AC full range input
•Fan Speed Control
•Energy Star
•Short Circuit Protection
•Over Voltage Protection
•20+4 pin: compatible with all motherboards available on the market

Connections

20 +4 pin x 1
Peripheral Power Connectors x 4
Floppy Power Connector x 1
SATA Power Connector x 4
PCI-E (6+2pin) x 2
ATX 12V 8pin (4+4 pin) x 1

Warranty: 1 Year Return To Base Warranty

be under less stress?

 

[paradisiac]

Difficult to say, can you find the ratings of the +12V rails? If they are around 40A each, this should suffice.

the psu comes in on monday so will have a look then. if its higher ratings than mine will swap it over.

 

[paradisiac]

ok, well the 800w psu is here and both +12v rails say 32A and mine is 30A, so would this be a worthwile upgrade?

 

[paradisiac]

ok, will give it a bash and see how it gets on, if not then will just hang on at 4.6GHz until the next gen gfx cards come out and do psu at same time.

im guessing as they are the same psu, just different wattage, i can just swap the psu but keep the cables from the old one? save me have to cable tidy again.