Increasing RAM on EP45-UD3P

[Alf928]

Hi all,

My current specs are:
Intel Q9550 E0 @ stock
Gigabyte EP45-UD3P v1.0, F8 BIOS
4GB (2x2) DDR2 Corsair Dominator PC-8500 (8500C5D), 5-5-5-15-2T, 2.1v, @ 1066MHz

BIOS flashed using Lsdmeasap's guide on this board. I loaded Optimized defaults. BIOS settings currently at AUTO for settings.

I've just obtained an extra 4GB of the same RAM. My questions are:
- Can I just drop the RAM into my system and leave settings alone, or would I need to do some tweaking in the BIOS at first boot after installation e.g. raise NB voltage?
- If I dropped the RAM from 1066 to 800, I would only be decreasing memory bandwidth correct?
- Is it better to manually set settings via the BIOS or via ET6 if I choose to bump my CPU FSB multi to 400?

Many thanks,
Alf

[Lsdmeasap]

Re: Increasing RAM on EP45-UD3P

Well you may be able to get away with doing that, but likely not. For 8GB you are going to have to for sure set your ram voltage to spec or above, and likely add some MCH Voltage. Maybe 1.24-1.34 MCH Voltage. You may also need to raise tRFC a bit manually, maybe 54-68

Use the BIOS to set things, use Easytune only for small tests using apply not save.

Yes, running your ram at 800-1000 would only drop a little bandwidth, but at lower speeds you can use tighter timings so it will be worth it. You will have a hard time running 8GB at 1006 without using excessive voltages or very loose and unnecessary timings so you should just expect/plan to run them at 900-1000 or so anyway

[Alf928]

Re: Increasing RAM on EP45-UD3P

Thanks Lsdmeasap. I'd like to clear up just a couple of items that I'm unsure about.

Well you may be able to get away with doing that, but likely not. For 8GB you are going to have to for sure set your ram voltage to spec or above, and likely add some MCH Voltage. Maybe 1.24-1.34 MCH Voltage. You may also need to raise tRFC a bit manually, maybe 54-68

How would I know if the MCH is lacking in voltage? And how would I test if tRFC is sufficient?

Yes, running your ram at 800-1000 would only drop a little bandwidth, but at lower speeds you can use tighter timings so it will be worth it.

I would probably run them at 800, however I've just had a look at my memory info through CPU-Z. The timings table is as follows:
For 270MHz, 4-4-4-13 (tRC 18, 1.8V)
For 400MHz, 5-5-5-18 (tRC 23, 1.8V)
For 533MHz, 5-5-5-15 (tRC 22, Command Rate 2T, 2.1V)

How come for 400MHz (which I believe equals to 800MHz as it's DDR - aka PC6400), the timings are looser than for 533 MHz (refering to the tRAS)?

I assume normally that the command rate is 1T, as it's not specified for 270 and 400MHz?


Thanks in advance.

[Psycho101]

Re: Increasing RAM on EP45-UD3P

How would I know if the MCH is lacking in voltage? And how would I test if tRFC is sufficient?

You would have to use a couple of stability testing programs. Mainly Memtest and Prime95/OCCT. Intel Burn Test may be good to use as a quick test, 5 runs should detect any major problems, but a Prime 95 run set to "Blend" for 12-24 hours will tell you almost for certain.

How come for 400MHz (which I believe equals to 800MHz as it's DDR - aka PC6400), the timings are looser than for 533 MHz (refering to the tRAS)?

DDR-800 timings are detailed as 5-5-5-18 because that's the certified JEDEC standard for PC2-6400. You will notice that it will indicate "JEDEC" above the 270 and 400 settings, but won't show JEDEC above the 533 setting. This is because the only two JDEC certified PC2-8500 timing settings are 6-6-6-18 and 7-7-7-21.

I can tell you with 99% certainty that you could run your RAM 2x2GB at DDR-400 with 4-4-4-12 timings, if you put 2.1V through them, theyre rated for the voltage so it's not a problem. You can of course run them 5-5-5-18 (likely even 5-5-5-15) at 1.8V. There's no certainty about getting 4x2GB going at 4-4-4-12 @ 2.1V though. I have cheaper XMS2 PC2-8500, and it's happy at 4-4-4-12 2.1V.

You can safely ignore the "2T" classification. Whether you can set 2T or 1T is all dependant on the memory controller. Some can handle 1T until a certain speed, then must have 2T in order to continue. In my opinion they shouldn't rate ram as 2T or 1T as it's incorrect to do so. They probably do it to avoid problems with people setting 1T and having trouble.

Unlike with DDR-SDRAM (not DDR2) 1T or 2T makes virtually no difference, especially on an Intel platform. Set it to 2T no matter the speed.

[Alf928]

Re: Increasing RAM on EP45-UD3P

Thanks for the comprehensive response guys. I've got 8GB in my system now, but still with default voltages (MCH 1.1v, RAM 2.1v). I've noticed there is a slight delay now with some tasks...I'm assuming this comes from the lack of voltage of the MCH?