E7500, 4ghz on AIR

The less voltage is probably because they're using later models to yours, even though the chip itself is identical, the manufacturing process that made them has been refined and the chip tolerances are tighter, allowing a lower voltage.

My guess is either the chip is still not getting enough power (not likely) or your FSB:RAM ratio has become less than optimal (more likely) or the RAM itself is slightly iffy (most likely). Make sure the RAM speed is at or below its rating, make sure the RAM voltage is correct for that speed, and if possible keep the RAM speed and the FSB at 1:1.

Another thought occurs: is your power supply powerful enough to pull the system? Remember that increasing the CPU voltage increases the draw on the +12V rail in the PSU, so in your case it might be just under/just over (depending on the OC).

How long does Prime95 run before the machine reboots?

Also bear in mind that you might have picked up a 'dud' chip. I had that once with two identical P4 631 3GHz chips, where the one hit 5.2GHz easily, yet when swapped with its twin it wouldn't go higher than 3.7GHz...

I found that keeping my bus low allowed me to achieve a lower voltage OC. Interesting that you say you lowered your bus prior to this clock. I would have thought that your bus speed could have have been the problem. I would try maxing out the multiplier first then nudging up the FSB. Although, running a voltage of 1.5 to maintain your clock seems very risky.

Raise the Nbridge voltage.

Thanks for quick replay,

I dont seem to have problems with temperature. I checked on this list of Tj max and I confirmed its 100°C for all E7000 chips. That was the pre-definition of RealTemp v3.0 and its still reading 59ºC as Max temp under full load (room temperature is 22ºC)

Have a look at my current stable settings:
E7500 @3.96Ghz, Vcore:1.46v, and I found this value as well “+12v”=12.51v
BUS: 360mhz (although I know that my MB can do 390mhz+ tested by me on another cpu, E6300)
RAM: 2.1v, 360mhz, 1:1 ratio, (all within manufacture limits, RAM has also been running before at 390mhz+ with no prob.)
FSB: auto (it has been in [auto] in a previous higher OC on another cpu. I tried 1,30v but the reaction was the same)
MCH: 1,60v (have tried the max 1,65 of the MB and didnt help)
PCI-X and PCI are locked at 100 and 33 respectively.




What is weird is that even when I lower the multiplier to 10x, I can only reach 370mhz under the same settings. Shouldn’t it be able to accept much more bus frequency at lower multiplier? Even feeding more power into MCH=1,65v and FSB=1,30v didn’t help to pass 370mhz.

Do you think this is the limits, I am running out of options!

Isnt the default latencies the ones listed on the right column of CPUz, the EPP #1 ?
VID is 1.3625v but as you can see it is now at 1.4625v (0,1v above limit)

The rest of the configuration is.
HDD = 2x western digital velociraptor on Raid 0 Matrix
HDD = 1x Maxtor 320gb
VGA = Nvidia GeFoce 7600GS 256mb passive cooling (I am not a gamer, I am a photographer that needs to work on LightRoom faster) :-)
DVD = 1 plextor
Sound = 1 creative 5.1 player (a cheap one)
TV = Leadtek 2000xp

Is that ok? Anyway, as I said I have tried to disconnect most of them and it still didnt improve my OC not even 4mhz!!!

Please share you calculations!

Hi, it could be your motherboard....Also the chips can differ a lot.....i would say return this one if you can and get a q9550, those are a blast and if you live close to a micro center you can pick one up for 160, E0 stepping. =]. Also anything over 1.4Vcore can decrease your chip's life. Its speed vs stability vs power consumption vs temps, you can always pick two out of the four, but not all four.