Asus P7P55D Series Discussion

**grenadier** · 10-11-2009, 03:36 PM

Currently running my i5 750 prime95 stable at 21x200. Only problem is that it takes 1.5V

. Load temps are 66C with my TRUE which aren't bad at all, but I'm still a bit nervous. Any tips on getting this voltage down while still maintaining stability? Is 1.5V even safe?

Full specs are in sig. RAM is running at stock speed / timings / voltages. Full voltages:
1.5V cpu, 1.25V imc, 1.5V dram, 1.15V PCH, 1.9V PLL

**Supershanks** · 10-11-2009, 03:49 PM

not needed to go up to 1.5v this was my 4.2Ghz on i5-750 bios settings are at bottom of post. Increasing PLL a notch may help, also CPU Amplitude & Skew.
1.375v Vcore
IMC Voltage 1.3000v
CPU PLL Voltage 1.90v

You shouldn't do much harm benching, but i don't think i'd use it 24/7

**grenadier** · 10-11-2009, 04:02 PM

Originally Posted by Supershanks

not needed to go up to 1.5v this was my 4.2Ghz on i5-750 bios settings are at bottom of post. Increasing PLL a notch may help, also CPU Amplitude & Skew.
1.375v Vcore
IMC Voltage 1.3000v
CPU PLL Voltage 1.90v

My CPU PLL voltage is already 1.9V. I shouldn't need more than 1.25V IMC voltage tops since I'm running my memory at 1600 using stock timings and 1.5V. Does anyone think in this situation that the memory controller really needs any extra voltage?

I changed my cpu amplitude / skew settings to match yours to see what would happen and it hasn't allowed me to get 4.2GHz stable at lower cpu voltages. Right now everything is prime95 stable at 4GHz / 1.45V / 21x191 / 1600. Increase the multi to 21 though and the voltage needs to be upped all the way to 1.5V to get any kind of stability (p95 stable for 1 hour before 1 core halted). Definitely going to stick to 4GHz unless anyone has any more tips...

Thanks for the reply!

EDIT: Dropping my IMC voltage to 1.2V has shaved 10C off my temps (89C to 79C) and doesn't impair stability at all. I think most folks simply don't need to pump this higher than 1.2V, which is what the xbitlabs article on the p7p55d deluxe article recommends.

**Supershanks** · 10-12-2009, 12:46 AM

that's an improvement nice one. Yes i'm running at 2000 so makes a difference on IMC

**lasty** · 10-12-2009, 01:04 AM

I have a quick question regarding voltages and hard crashes (freezes, no blue screens). I'm running an 860 at 3.8ghz with 1.3125v Vcore, 1.3v IMC, 1.65v DDR, and 1.8v PLL. My memory is running at 1900mhz 7-8-7-20 1T (4gb kingston 2000mhz C8 kit). With the voltages mentioned i've run memtest86+ v4.00 for 5hours without any errors. Can i conclude that the DDR+IMC voltages are ok then? I mean, only vcore&pll could cause the instability now?

I did up the PLL to 1.9v and this did seem to improve stability, but was recommended not to use this voltage for 24/7 use. (see the other asus p7p55d discussion in the reviews forum) What are your experiences on the voltages? Can i also try to lower the IMC voltage and test with memtest86+ for stability, or do i need to run prime for absolute memory stability testing?

I'm a bit new to ovverclocking and would like to take it one step at a time. preferably looking at stable memory voltages/timings first before increasing the cpu speed. Is this a good approach?

Sorry for the question spamming

**Hockster** · 10-12-2009, 01:37 AM

I've got my 860 at 3.68 using only 1.25 volts and 1.8 on the PLL. Only a 167 bclck though. Not sue if that makes much difference or not.

**ezaleina** · 10-12-2009, 05:40 AM

hi all.,sorry off topic abit.,can i know where can i get TRUE bracket for 1156..

**melyee** · 10-12-2009, 08:26 AM

Originally Posted by grenadier

My CPU PLL voltage is already 1.9V. I shouldn't need more than 1.25V IMC voltage tops since I'm running my memory at 1600 using stock timings and 1.5V. Does anyone think in this situation that the memory controller really needs any extra voltage?

I changed my cpu amplitude / skew settings to match yours to see what would happen and it hasn't allowed me to get 4.2GHz stable at lower cpu voltages. Right now everything is prime95 stable at 4GHz / 1.45V / 21x191 / 1600. Increase the multi to 21 though and the voltage needs to be upped all the way to 1.5V to get any kind of stability (p95 stable for 1 hour before 1 core halted). Definitely going to stick to 4GHz unless anyone has any more tips...

Thanks for the reply!

EDIT: Dropping my IMC voltage to 1.2V has shaved 10C off my temps (89C to 79C) and doesn't impair stability at all. I think most folks simply don't need to pump this higher than 1.2V, which is what the xbitlabs article on the p7p55d deluxe article recommends.

Is there any benefits on doing 191x21 instead of 200x20?
Cuz I'm running my i5@200x20@1.375v...IMC 1.225v. I think increase BCLK gains better performance than multiplier, right?

**unclewebb** · 10-12-2009, 09:10 AM

On the original Core i7-9xx series, a lot of users had an easier time getting 191x21 stable compared to 200x20. The odd multipliers seemed to need less core voltage which helped keep the temps down too a few degrees. I'm not sure if the new socket 1156 chips are the same or not. I guess do some testing, run some benches and let us know what you find.

**grenadier** · 10-12-2009, 06:09 PM

Changed around a bunch more settings. 4GHz just takes too much voltage no way around it - one core in particular keeps quitting on me

even at 1.5V this core crashes out of p95 after an hour while the other three are happy to keep chugging along all night. Think this is the chip not the board or any other part of the setup so now I'm just trying to get everything rock stable on as little voltage as possible so I can bring my temps / fan speeds down.

Best blend of speed / stability / temps I've found so far is 3.8GHz (21 x 181) with 1.35V cpu, 1.2V IMC, 1.9V PLL, and 1.15V PCH. Prime95 temps are topping out around only 70C with all my fans turned down to 5V

. IMC voltage contributes A LOT to the high temps many of you are seeing since you're essentially pumping another .1-.25V right into the cpu. Keeping IMC voltage DOWN by using a higher multi / lower bclk combo will decrease temps and increase stability.

When I have more time I'm going to see if I can keep this setup stable at even lower voltages. Maybe 3.8GHz with 1.1V IMC and 1.3V cpu is possible? If I can come up with some $ I may switch to an i7 860 just so I can try for 4GHz (25x160) using lower cpu and IMC voltages. With a 1:5 DRAM ratio that 160 blck would be perfect for my g.skill 1600 (5x160=800) too

.

EDIT: Tried for 3.9GHz / 1.36V cpu / 1.2V IMC, but it's not completely stable - one core crashed again after ~5 hours of prime. I'm giving up on anything over 3.8GHz so now I'm just trying to find the lowest voltages / temps for a decent overclock in the 3.5-3.8GHz range. Currently dropped to 3.6GHz (21x171) with 1.275V cpu & 1.15V IMC - prime95 temps are down another 10 degrees to 60C.

**GrossmeisterB** · 10-12-2009, 09:35 PM

The strange thing is: it seems a lot of people here are having trouble, getting their i5-750's stable at 20x200MHz, even with a lot of Vcore...in some german forum, a lot of peope get their i7-750 stable, with voltages of 1.35V and below...my own CPU is somewhere in between, with 1.384V for 20x200Mhz...
Now what's wrong here? Did you guys in the US got other batches? Or what's the point?

**GrossmeisterB** · 10-13-2009, 03:55 AM

Originally Posted by Retro

That's been the case for years now with cpu's, call it luck of the draw, or where on the wafer the chip was cut from, if there was a full moon, etc.
Maybe there is a higher percentage of "good" chips in Germany right now, but there are a few examples of people getting good stability with i5 750's at 4000MHz and above with less than 1.4000v even here at XSF.

Or as they say in the US: "YMMV" : "Your Mileage May Vary"

I know that this is "luck", but it is really strange, that it's "high voltage" in the US and "low voltage" in germany...
But I think we gotta wait a little bit longer, until a few more people have their rigs up and running...

**Porksmuggler** · 10-14-2009, 10:40 PM

before you do any high voltage OC with the P7P55D, maybe read this first

http://www.anandtech.com/mb/showdoc.aspx?i=3661

ASUS boards apparently all use the Foxconn socket

**CikaNovo** · 10-15-2009, 07:03 AM

Hello everyone.

Justa a quick question: Can you mount Ultra 120 extreme in north-south position on this mobo with all ram slots populated.Also, will it be touching graphics card if it is mounted this way.

Thanks

**Supershanks** · 10-15-2009, 07:22 AM

Should be no problem if your using low profile modules
see below.
Click Pic for more detail

**CikaNovo** · 10-15-2009, 09:24 AM

Ok,thank you Supershanks.
What about graphics card in first slot.Do you think TRUE 120 Ex. mounted in north-south position will be touching the card in first slot?

**Hockster** · 10-15-2009, 09:50 AM

I'm using a Zalman CNPS 10X cooler mounted that way, I think it's a bit larger than my TRUE, and it clears the memory and video cards. But as the above pic shows you'll need low profile memory.
Bit of a crappy pic, my rig is kinda tight to access for a few pics.

**CikaNovo** · 10-15-2009, 10:26 AM

Looks like it's very close to both: graphics card and memory but still, it fits.
I see you are running Crossfire. Since graphics cards are only two slots apart I assume the upper card shows much higher temperatures. What's the temp. difference between the cards?

**Supershanks** · 10-15-2009, 10:40 AM

aye that's right good pick Hockster

Sounds daft, but i put some masking tape along the backside of the card just to prevent shorts. I'm a clumsy sod and knowing me will catch cooler and knock it aq couple of mm into back of live gfx card

**BababooeyHTJ** · 10-15-2009, 06:44 PM

Originally Posted by Supershanks

aye well hopefully , it's just you ram that's the issue. That would be best result.
Yes the Ripjaw is great, i'm running with 2 sets of it, great stuff .

I'm looking at this board and an i5 750.

Anyways, is there any reason to get the 1600mhz cas7 kit over the 2000 cas9 kit?

How is the vrm cooling on this board? I have to ask since it was very subpar on my P5QD.

**Retro** · 10-15-2009, 10:03 PM

Originally Posted by BababooeyHTJ

I'm looking at this board and an i5 750.

Anyways, is there any reason to get the 1600mhz cas7 kit over the 2000 cas9 kit?

How is the vrm cooling on this board? I have to ask since it was very subpar on my P5QD.

Go for it

I bought the 2000 kit for more headroom, but at the settings I am using it is happy with cas 8 or even 7, very versatile kit. Really pleased with the GSkill Ripjaws.
Have a look at Supershanks review and thread on the P7P55 D Deluxe if you haven't yet, lots of good info. there.
The Deluxe has a heatpipe connecting the vrm sinks, so it should be even better than the cooling on the Pro which just uses two sinks.
I've found this board to be fine with the stock sinks, compared to the P5Q Pro it replaced.
No heat issues with the Pro at it's current 24/7 overclock so far

**Supershanks** · 10-15-2009, 10:18 PM

as retro said, the ptemium for the 2000 over the 1600 was around 10% but the extra rated speed is 25%. That sounds decent vakuer to me.

As retro says therey hive plenty of flexibility at lower speeds, thighter timings as well as having the headroom.

no issues on cooling.

**Hockster** · 10-16-2009, 12:53 AM

Originally Posted by CikaNovo

Looks like it's very close to both: graphics card and memory but still, it fits.
I see you are running Crossfire. Since graphics cards are only two slots apart I assume the upper card shows much higher temperatures. What's the temp. difference between the cards?

They're actually quite close to each other. Only a couple of degrees separate them. I do have a couple 120mm fans mounted in the side panel of my case. I wasn't terribly impressed with the stock Cosmos cooling, only 1 intake fan.

**CikaNovo** · 10-16-2009, 08:45 AM

I have side panel off on my case and temp. difference between the cards goes as high as 8 degrees C when they are under load.
That is with 3 slots between them. I'm afraid that if I use one of the p7p55 boards that only have 2 slots separating graphics cards, the difference will be even bigger.

**Marco André** · 10-24-2009, 08:40 AM

Some love from Portugal

Asus P7P55D EVO

Asus P7P55D Deluxe

i750 overclocked to 4.4+ on air

Thread: Asus P7P55D Series Discussion

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