e6300 performance dip past 2.8ghz ?

I've not seen these performance dips either but then I haven't been looking - might have to do some testing.

I am curious though since support for 1333MHz FSB wasn't introduced on the DS3 until the F9 BIOS, and that is only for rev 3.3. Is this strap change BIOS dependent and how would it affect anybody using BIOS prior to F9?
 
Sniper123 said:
If there is a proformance dip either superPI hide's it well :p
SuperPI mod
6300 @ 3.4GHz 5-5-5-15 = 16.547s (490*7)
6300 @ 3.2GHz 5-5-5-15 = 17.8**s (465*7)
6300 @ 3.0GHz 5-5-5-15 = 19.***s (430*7)
6300 @ 2.8GHz 5-5-5-15 = 20.5**s (400*7)


Result's are from memory apart from 3.4GHz, But if the strap issue was bad then I think 400/430*7 would have about the same superPI result (guessing!) :D
Click to expand...

Run the 32m test. Pi 1m firstly is harder to see a difference, and secondly fits pretty much totally in cache so doesn't rely as much on memory speeds.
Also run 390 -> 490. Strap change is ~ 400 FSB which means it might not fall exactly at 400 FSB :)
 
"Performance dip" is not the best term to describe it.

Strap is a set of internal latencies within the chipset/northbridge, which work like memory latencies and are important to overall system performance.

But since the memory controller is integrated in the chipset, this set of "strap" settings directly relate to memory performance, aka bandwidth.

So if you have to refer to it as a "dip", it's more of a bandwidth dip, rather than a "performance dip".

The Pi results aren't indicative of this, because higher CPU clocks do offset bandwidth dip, since crunching Pi mainly depends on CPU arithmetic power. =)

Strap 1333 basically loosens chipset timings/latencies in order to offer higher FSB to achieve higher CPU clocks (which is more important to the system as a whole). It's like the controversial discussion of latencies vs mem clocks for AMD/Intel architecture.

Either you work efficiently (tighter latencies) at lower clocks, or you slack off a bit to achieve higher clocks. And as the clocks go higher and higher (past 467Mhz for P965), the bandwidth will rise again. But Pi times will have always improved due to faster CPU speed.

Hope that helps =)
 
smsmasters said:
Yikes, I was going to buy an Asus P5B Deluxe AP board but I'm weary now.
Click to expand...
Don't worry about it, the P5B-Deluxe is a great board.

I've done a bit of reading on this subject but not yet had time to do some testing, which would involved setting a certain FSB in BIOS, booting to windows and running some memory sensitive benchmarks. The way being suggested to get around this is to boot at 400MHz-FSB and then use software overclocking (Clockgen) to raise the FSB, doing it this way means the MCH doesn't flick to the slower 1333 strap.

Can't say this is a problem myself but I will test it out properly when I get time (unless one of our forum members does it first).

I think 400MHz-FSB uses the faster strap, but 401MHz-450/460MHz at boot means the chipset changes to the slower strap. However for some reason once you get past approx 460MHz-FSB (at boot) the strap changes?

People are reffering to this as a 'FSB Black-Hole' lol :p
 
To illustrate the performance hit, ran a few tests on the P5N-E a while back. The board switches strap at ~ 425 FSB. Running Pi 32M at various FSB's around this shows the performance drop from the strap change.

423 FSB
423_pi1m.JPG


425 FSB
425_pi1m.JPG


426 FSB
426_pi1m.JPG
 
so can someone confirm whats the best frequency to 'JUMP' to after 400mhz FSB to avoid all this strap/memory performance loss/chipset running nr its max on any one strap malarky !

I have a p5b deluxe by the way. 2.8ghz is working a dream with temps at idle at around 32-34c but i wanna try to go more just because ppl are saying its so easy !
 
Arge said:
2.8ghz is working a dream with temps at idle at around 32-34c
Click to expand...
try and include load temps as well, i.e 32-34°C Idle/ 60°C Tat Load.

There is almost no reason 'ever' to reference idle temps alone.
 
ok, 52/53c at TAT 100% load. actually, this is edging close to the recommended 60c max !??

what temps are others getting at 100% load with their overclocks ?
oh yeh and what cooler !
mines a ac freezer 7 pro.
 
You must log in or register to reply here.
Back
Top Bottom