ASUS M4N78-PRO - RAM upgrade

caracal

Honorable
Aug 16, 2012
2
0
10,510
Hi,

I want to do a RAM upgrade since 4GB just isn't enough for my activities these days, even just random web surfing.
My PC: (desktop) 2009 vintage.
The motherboard is ASUS M4N78-PRO, with AMD Phenom™ II X4 810 CPU.

There are 4 RAM slots, two taken up with Kingston KHX8500D2K2/4G ( CL5) 4GB (2GB x 2) HYPERX 1066MHz(PC2-8500) DDR2 kit CL5 (5-5-5-15).
this one:
http://www.pccasegear.com/index.php?main_page=product_info&products_id=17861

I'm running 32bit WINXP with the associated <4GB limit, however, I intend to put 64bit WIN7 Pro on the 2nd hard disk and dual boot it (thus use the extra memory when running Win 7.)

The motherboard seems to only take DDR-2 RAM, it also seems to have limits on the mHz of RAM which I'm a bit confused.

http://www.asus.com/Motherboards/AMD_AM2Plus/M4N78_PRO/#specifications

"Memory: 4 x DIMM, Max. 16 GB, DDR2 1200(O.C.)/1066*/800/667 ECC,Non-ECC,Un-buffered Memory
Dual Channel memory architecture
*Due to AMD CPU limitation, DDR2 1066 is supported by AM2+/AM3 CPU for one DIMM per channel only. Refer to www.asus.com for the memory QVL (Qualified Vendors Lists). "

Does this mean it only supports 1200 when overclocked? There seems to be a limit on the 1066 memory also. Kingston site
http://www.kingston.com/us/memory/search/Default.aspx?DeviceType=7&Mfr=ASU&Line=M4%20Motherboard&Model=56778

claims that "Maximum Memory:
2GB using DDR2-1066 in one DIMM channel
16GB using DDR2-667/800"

But the 4GB of 1066 memory currently in there seems to work fine (I don't know what speed it's running at, but Windows claims 3.25GB RAM as expected.) Is there a reason to/not buy 1066 vs 800mHz? (eg. they will or won't run at 1066). Kingston's 'advisor' only brings up 800mHz results.
The Crucial site 'recommends' this as compatible:

8GB Kit (4GBx2), 240-pin DIMM, DDR2 PC2-5300 memory module

Part Number: CT2KIT51264AA667
Module Size: 8GB Kit (4GBx2)
Package: 240-pin DIMM
Feature: DDR2 PC2-5300
Specs: DDR2 PC2-5300 • CL=5 • Unbuffered • NON-ECC • DDR2-667 • 1.8V • 512Meg x 64 •

As you can see this is only 667 mHz. All the other 'recommended' ones (Kingston site, approved by ASUS list from 2009, etc.) are 2x2GB or less, in fact in online stores I only see 2x2GB DDR-2 RAM kits in general, this is the only 8gb pair I've seen thus far.

But it sounds like an extra 8GB of (lower quality?) RAM at a slower speed is better than only another 4GB at a faster speed. If not, I guess I can just get another pair of the type I have (it's still sold, it seems). Is there a reason why it won't work? (I'm making the possibly wrong assumption that if the maximum 1066 is used up, the other RAM just runs at a lower speed, rather than ceasing to work/causing errors etc?) Any suggestion of other products also appreciated, I just don't know how to tell it will work, apart from the manufacturer sites claiming so. Corsair simply didn't have that motherboard in its online tool. etc.

Thanks!
 
G

Guest

Guest
I have the same question too - I've got a M4N78 Pro, with 4GB 1066 8500 DDR2 ram. I've just upgraded from 32 to 64 bit (linux - Ubuntu), and was thinking I could now take advantage of extra RAM, but will I be limited to 800MHz, and how will 8GB 800MHz (as I assume my existing 1066 will underclock down) perform compared to 4GB 1066?
Can anyone help??
Thanks.