Q9450 max vcore and temps?

[Frostex]

I've grabbed the Asus P5E with a Q9450 and 4Gb of PC2-8500 RAM

Currently I have vcore set at auto and the chip clicked at 8x450 which is 3.6Ghz, vcore on Asus probe II is showing 1.38v idle and strangely 1.33v under full load

It cooled by the Zalman 9700 which is an awesome HSF combo I must say, 29 degrees Idle and 47 degrees under full load (prime 95 in place large FFT's torture test x4)

It's prime95 stable overnight at these settings. However if I try and push much further like for 3.7ghz i start getting instabilities and booting can fail, so I'm looking at possibly pushing further by tweaking the voltage up a bit

What sort of safe maximum can it go up to? I really cannot afford to blow this chip by feeding it too much voltage since this rig cost £1300 to throw together and I dont have any money to replace it

Any info would be great, thanks

 

[BillParrish]

As to what your core can stand - only you can find out.

Intel datasheet says 1.45V Vcore is the absolute maximum voltage rating for that chip.

Intel VRM (CPU voltage regulator) specifications allow a .05V "overshoot" for short periods of time as the regulator tries to compensate during transitions from light load to heavy load like starting up a game of starting Orthos or Prime. There is no guarantee that your board maker meets the Intel spec.

People have pushed them higher, but unless you are unconcerned (and you mention you are concerned) about the cost of replacing the CPU, I recommend you use a 1.40V maximum and 1.385 might even be a better personal limit. The question I ask myself "is the next bump in voltage worth 100MHz vs a new CPU."

Good news is you cannot burn it up with heat, it will just first signal it is hot (delta to Tjmax = 0) then if it gets hotter at some point it will just shutdown in an attempt to save itself. Not really something you want to test however. Use any good temp program and use the option to display "delta to Tjmax" that will tell you in deg C how much headroom (it works like a countdown timer) you have before the CPU thinks it is getting too hot. A 10-15 deg margin under full load is more than sufficient but of course the greater the margin (cooler) the better.

 

[Frostex]

I've just read about a bit else where on anand and xbit and it seems that 3.6 is actually quite a reasonable overclock, especially at them temps (on air) Im sure I read about people getting them to 3.8 and 4.0ghz but I'm fairly certain you're right, when it comes down to it the additional 100Mhz is not worth damaging the chip (however that might happen)

going to leave the voltage on auto (1.38v idle and 1.33v under load as above) I may try and drop that over the next few days just for less heat and hopefuly keep the chip stable and give it a longer lifespan.

my next question is, with a 450FBS and RAM effectively running at 900Mhz DDR which is capable of 1066Mhz DDR, is it worth putting the RAM higher and running out of sync? Or is 1:1 better than a 166Mhz ram speed jump?

 

[BillParrish]

I used to be a huge proponent of 1:1 when ram was expensive and the high speed stuff was ridiculous in price.

It is certainly true you will take a minor performance hit using a multiplier that is not one to one as "everyone in the boat is not rowing at the same speed" and buffering and wait states must happen to keep things in step. However almost all the time the increase in memory bandwidth is worth it and you come out ahead in performance. The other thing is that you paid for that nice ram so it is well worth the time to try it at the lowest (next highest) multiplier and even if you have to loosen the timings a bit, see what it will do. All you can do is try 5/4 (or 1.2 or whatever your lowest multiplier other than 1:1) is and see. You might need to run some kind of benchmark to really see and if you can find a nice stable "sweet spot" I would use the machine for a week in each setting because sometimes you can "feel/see" stuff that a benchmark does not really express or conversely you might have an application/game that does not like the higher speed memory setting. This is the "fun" bit if you like to "play". Enjoy.