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GA-P55-UD3R with G.SKILL or Corsair?

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Last response: in Motherboards
October 12, 2009 12:58:16 AM

I'm looking at the GA-P55-UD3R mother board. Somebody suggested using this memory from G.SKILL:
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL7D-4GBRH - Retail

How does this compare to using Corsair memory? This is listed at 1.5v which is what Gigabyte is asking for on their spec page, while the G.SKILL is 1.65v.
CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 Desktop Memory Model TW3X4G1333C9A G

What happens in either case if you go to the 8GB (4 x 2GB)?



More about : p55 ud3r skill corsair

a b } Memory
a c 178 V Motherboard
October 12, 2009 2:05:58 AM

I'd go with the G.Skill - the memory frequency doesn't matter much to the i5/i7 - what matters is the latency; P55 setups are only rated by Intel for a 1333 RAM frequency - that G.Skill will likely run 6-6-6-20 at the same 1333 that the Corsair (9-9-9-24) is rated at. Don't worry about the voltage - 1.65 is pretty much standard for all faster i7/i5 RAM, and isn't a problem; likewise, if you want to go to 8G, it's just a matter of tweaking a couple voltages a bit - and, that G.Skill may well run at the 1333 speed at 1.5V as well...

Latency is a term for the time the CPU must wait for RAM to complete cetain operations, and it's given in counts of clock cycles - so, the fewer counts waited, the faster the throughput...
October 13, 2009 5:00:44 PM

I just built a i5 system with that Gigabyte board, and the GSkli RAM you have there. It started right up no problems. Memtest was fine. The GSkil runs at 9-9-9-24...1333MHz.

Good luck.

Oh, and Win 7 x64 loaded in ~15 minutes (WD Caviar Black HD) from a bootable USB drive.

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October 14, 2009 2:06:54 PM

How much ram did you put in?

I am reading about many problems people are having when they go to 4 sticks.

I'm fighting that very issue with a friends GA-EP45-UD3R so I really don't want to go through that pain.
a b } Memory
a c 178 V Motherboard
October 14, 2009 3:13:51 PM

I'm fighting that very issue with a friends GA-EP45-UD3R so I really don't want to go through that pain.

Post me the processor, and the RAM P/N, and I'll give you settings for four sticks - it's not all that hard; basically, you need to do a "Load Optimized Defaults" to get the right underlying memory settings, check that your DDR voltage is set to mfg's spec (usually 2.1V), then 'bump' the MCH voltage a tenth, or even a tenth and a half, to accommodate the four sticks...
October 14, 2009 8:53:57 PM


CPU is Q9550
The memory is Corsair CM2X2048-8500CC5D, 2.10v
The motherboard is Gigabyte GA-EP45-UD3R (v1.1)

What is the MCH voltage?
a b } Memory
a c 178 V Motherboard
October 14, 2009 10:06:26 PM

MCH (memory control hub) is another name for the 'northbridge' - the primary manager of the memory, and the thing that handles all communications (to and from the CPU) with the rest of the board's hardware... It is the P45, from which your board gets its part number/name. We are going to go into the system BIOS to make some changes; you might want to review page 36 in your manual in the meantime, regarding the keystrokes to get into the BIOS itself, and maybe try it a few times until you're comfortable with it. Don't change anything - and, no matter where you are, a few <escapes> will get you out - when it asks you "Exit without saving changes?", just confirm it, and you'll get a reboot...

The BIOS (basic input output system) is boot firmware, designed to be the first code run by a PC when powered on. The initial function of the BIOS is to identify, test, and initialize system devices such as the video display card, hard disk, floppy disk and other hardware. The BIOS prepares the machine for a known state, so that software stored on compatible media can be loaded, executed, and given control of the PC - this process is known as booting, or booting up, which is short for bootstrapping. One of its first jobs is to 'talk' to the P45, and configure your memory controller for use...

If you'd like a little bit of a 'virtual tour' of the BIOS in the meantime, take a peek here:

I have one more question for you: do you guys have any aftermarket cooler on the CPU? If you do, I'll include a mild, no-risk, low-voltage 20% overclock that will speed up the machine enough for you to notice it - but, it's not really a good idea to do this with the stock Intel cooler that came with the chip...

a c 113 } Memory
a c 500 V Motherboard
October 14, 2009 11:19:58 PM

bn_hot said:
How much ram did you put in?

I am reading about many problems people are having when they go to 4 sticks.

I'm fighting that very issue with a friends GA-EP45-UD3R so I really don't want to go through that pain.

I run 8 GB of G.Skill PI Black DDR2-800 at 4-4-4-12 timings and 1.9V in my GA-EP45-UD3P and it's stable.
October 15, 2009 1:42:25 AM

It is the stock cooler right now, but I will likely replace it as the fan makes a clicking noise (gotta love quality control). I'm very much open to cheap suggestions, so if you would include that with your overclock recommendation... :) 

But I'll also need the non overclock settings too :) 


Best solution

a b } Memory
a c 178 V Motherboard
October 15, 2009 2:47:41 AM

You don't have to spend a lot, or get nuts about it - any damn thing you can buy in the 'aftermarket' will beat the pants off Intel's included 'rotary postage stamp... I often recommend these:
as they are well made, get the job done, and are small enough to fit in nearly anyone's rig (you're a little late - I just gave one away to someone here for the cost of shipping - it was 'unemployed' and I felt sorry for the poor little thing!), but, truth be told, even this:
will handle this overclock, and be head and shoulders above the stock piece...

I have searched extensively, and cannot find that Corsair #; it may just no longer be an active P/N, or they might have renamed it (they recently transitioned a whole bunch of stuff to a 'TWINX2' designation), but it shouldn't matter - the first step in the process will cause your system to 'read' the RAM, and set itself accordingly - usually works just fine...

To get a mild, safe, low-voltage (but noticeable) 20% overclock (when you get anything else but stock cooling), the italicized

parameters are all that need be changed...

Intel Q9550 1333FSB x8.5mult 2.83GHz/3.4GHz .85-1.3625V
Corsair CM2X2048-8500CC5D 8GB (4 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 memory: 5-5-5-15-2t nominal 2.1v (I think...)

If you haven't yet done it, pull out two sticks, leave two in the slots labeled "DDR2_1" and "DDR2_3" (I think, on your board, it's the orange pair), and start with a BIOS' "Load Optimized Defaults" - save, exit, and reboot...

Before we start ramping things up, I want to teach you a skill involving the BIOS: Do the <DEL> at the boot to enter the BIOS; notice, at the bottom, the <F11> "Save CMOS to BIOS" - hit this, and you should get a menu that will show a number (the count varies by BIOS) of empty 'slots', each of which will store an entire set of BIOS parameters, to be re-loaded from the corresponding <F12> "Load CMOS from BIOS"; this is a wonderful overclocker's feature. What I do with it, is to save my 'baseline' working parameters, so if I change something that 'irritates' the board, and forces a reset of all the parameters to defaults, or, even worse, get so screwed up I need to do a 'clear CMOS', I can get back to my starting point with no effort, and without having to remember 85 separate settings! Another thing it prevents is two hours' troubleshooting, having forgotten a change to a crucial parameter - like, "wait a minute - didn't I have the tRD at seven?!" It's pretty self-explanatory, and I always urge people to start right away by taking the time to give the 'slots' names that mean something: in two hours, "Try2" and "Try3" will not be very helpful, but "450@+10MCH" and "450@+15MCH" will! Another use is for 'green' settings; overclocks, as a rule, do not 'play well' with green features, such as 'down-clocking' and 'down-volting'; with the storage slots, you can set up one profile, say "Green", with all the settings at 'stock' values, and all the 'green' features enabled; another, say "Balls2Wall" with a full overclock, and all the 'green' stuff turned off... Another neat feature of this 'slot' system is, for most BIOS, the mechanism itself will keep track of which ones have booted successfully, and how many times (up to, I believe, a max of five)!

In the BIOS, on the "Advanced BIOS Features" page:

"CPU Enhanced Halt (C1E)" to "Disabled"
"C2/C2E State Support" to "Disabled"
"C4/C4E State Support" to "Disabled"
"CPU Thermal Monitor 2 (TM2)" to "Enabled"
"CPU EIST Function" to "Disabled"
"Virtualization Technology" to "Enabled" - this allows use of Win7's fantastic VirtualXp feature...
"Full Screen LOGO Show" to "Disabled"

On the "Integrated Peripherals" page:

Your manual shows "Legacy USB storage detect", but later BIOS say "USB Storage Function" - either way, set to "Disabled"

On the "Power Management Setup" page:

"ACPI Suspend Type" to "S1(POS)" (for now...)
"HPET Support" to "Enabled"
"HPET Mode" to whichever OS type you're running - "32-bit" if an x86 version, "64-bit" if an x64 version...

On the "MB Intelligent Tweaker(M.I.T.)" page:

"Robust Graphics Booster" to "Auto"
"CPU Clock Ratio" to "8"
"Fine CPU Clock Ratio" to ".5"
"CPU Frequency" - this one can't be set, it's calculated, and will change when we set the next few items...

******** Clock Chip Control ********
>>>>> Standard Clock Control

"CPU Host Clock Control" to "Enabled"
"CPU Host Frequency (Mhz)" to "334"
"CPU Host Frequency (Mhz)" to "401"
"PCI Express Frequency (Mhz)" to "100" (not auto...)
"C.I.A.2" to "Disabled"

******** DRAM Performance Control ********
"Performance Enhance" to "Standard"
"Extreme Memory Profile (X.M.P.)" to "Disabled"

"(G)MCH Frequency Latch" to "333"
"System Memory Multiplier (SPD)" to "3.20B"
"(G)MCH Frequency Latch" to "400"
"System Memory Multiplier (SPD)" to "2.66D"

The "(G)MCH Frequency Latch" which we mostly refer to as a 'strap', is the reason we used a 334 or 401 clock instead of a nice even 333 or 400: the 'straps' are sets of northbridge timings - much like memory latencies, the faster you go, the 'looser' the timings have to be... There are four straps, corresponding to the Intel FSB ratings: 200 (800FSB), 266 (1066FSB), 333 (1333FSB), and 400 (1600FSB); each strap has its own set of available memory multipliers (ratios).The strap latencies, for some northbridges, don't 'kick in' until one over the selected strap; so, in other words, setting the clock to 334 guarantees that we're getting the 333 latencies/timings...

"Memory Frequency (Mhz)" - again, can't be set, it's calculated...
"DRAM Timing Selectable (SPD)" to "Manual"
You should be able to leave the rest of the memory settings alone; we haven't changed its actual speed, so it should keep working...

"Load-Line Calibration" to "Disabled" (this works differently on different boards - on mine, it's worse "enabled" than "disabled" - the function is supposed to cure a phenomenon called Vdroop - the CPU voltage regulation circuit causes the CPU core voltage to sag, or 'droop' under high loadings; hopefullt, we're going to be at a low enough voltage to just ignore this...)
"CPU Vcore" to "Auto"
"CPU Vcore" to "1.3250V"
"MCH Core" to 1.200V"
& check that "DRAM Voltage" is set to "2.100V" (this should have been done by the earlier "Load Optimized", but sometimes it doesn't work right...)

And that should do it!

I should point out that getting two reboots in a row here is perfectly normal behavior; it seems that, when you change certain settings (and we don't exactly know which ones - the only sure one I know is Trd - if you change it, I think you get the 'twin' reboot) it boots once to 'see where it's at', recalculates its remaining 'auto' settings, saves them, and then boots again. Three reboots in a row, however, usually indicates that the board was 'given indigestion' by your settings, and is going back to defaults. This sometimes goes astray, and it doesn't get back into proper operation - for example, at this point, mine will sometimes 'lock' itself into 111MHz x a six multiplier - and take a week to do a whole boot - that's time to do a CMOS reset, and use your 'stored' <F12> profile to get back to where you were...

Once this procedure has been completed, and you're booting normally, you can shut down and replace the other two DIMMs.

Good luck!


October 16, 2009 4:20:39 AM

I just applied the changes. System booted up fine, no issue, so I added the additional two sticks. I ran windows update, installed the latest nvidia and adobe. Now I'm going to let it sit for at least the next 12-24 hours and see how it holds up. Hopefully it won't crash on me like it was... :)  I'll post updates as I go, but thank you very much for your help Bill!!!
a b } Memory
a c 178 V Motherboard
October 16, 2009 5:24:05 PM

Always welcome!

Good luck - any further questions, feel free...

October 18, 2009 12:43:03 AM

That seems to have nailed it perfectly!!! Thank you very much!!!

Coming back to the original part of this thread, I am still looking to build using GA-P55-UD3R ( Not sure moving up to the GA-P55-UD4P makes sense (if it does, somebody please tell me why)

I am currently struggling with what memory to buy, wanting to get 4 x 2GB sticks for 8GB. I have bought many sticks from Corsair, but am open to suggestions. If there is something else I should consider, I would like to hear what and why.

Some of the memory is 1.65v, which from some things I read at the maximum of what P55 mobo will tolerate. Gigabyte is recommending 1.5v memory so that seems to make sense. Bill, I know above you said 1.65v is ok, but I'd like to better understand.

Also, if as above you have a recommendation for a low risk air cooled OC... and what cooler for this board?

A thousand thank you(s)!!!

EDIT: I was looking at Corsair just to see what might be there in the 1.65v range... found this:
Any thoughts?
EDIT2: Looking at the i5-750 CPU