ASUS M4A79XTD EVO compatibility check

[johnnystuff]

Hi all, I'm new here and luckily without any issue (yet). Of course, I'm asking for an update soon to come (as soon as you'll clarify my doubts).
I'm happy with my mobo and my Phenom II AMD X3 720 (C2 step) upgraded to a fully working X4 3.4Ghz one.
Now, I've been reading pretty much these days to try to get what can be tricky when upgrading ram on a quite old mobo and an amd cpu. So I decided to be somehow conservative and do not try to get the 1600 ones but try to max out my 4 slots with 4x4Gb 1333 sticks.
My mobo should support up to 32 Gb (they say/claim) and any voltage from 1.5 to 2.5V but I'm far from being optimistic when going to buy "only" 16 and let them work in dual channel. Fortunately I've read this from your general section:

Max DDR3 and DDR2 on AMD motherboards
I just got a reply back from Gigabyte about running the 16GB max stated on their site for my AM3 mobo and I'm sure a few others. I asked what type and speed RAM I would run to get the 16GB. I was curious and don't intend on running that much. Here is their reply. ( The more memory installed in a system, the harder to synchronize at faster speed and there will also be limitations on the AMD memory controller. For example can run 1600MHz but 1 DIMM per channel maximum. If you have 4 DIMMs, 1333MHz is the maximum supported memory speed. If going to load it up with 16GB, stick to standard DDR3 memory like 1066MHz or 1333MHz 1.5v memory. Thank you.)

So, these where the sticks I wanted to buy (in order of preference):
1- Ripjaws-X F3-10666CL7Q-16GBXH 1333MHz 16GB (4x4GB) CL7-7-7-21 1.5v
2- Ripjaws-X F3-10666CL7D-8GBXH 1333MHz 8GB (2x4GB) CL7-7-7-21 1.5v
3- Sniper 8GBSR 1.5V CL9

here come the questions:
1- do 1 and 2 just differ in the size amount, being buying two n?2 the same as one n?1?
2- the vendor list shows all these sticks compatible both for INTEL Socket 1155/1156 and AMD AM3 while in the specs I can see only intel mobo supported by 1-2 and an asus M4A79T Deluxe mobo for n?3, which is almost as mine with a 790FX NB instead of 790X (no 16x xfire/sli support on mine). Can you confirm that 1 and 2 are ok with my mobo/cpu? In case the answer is "no" could I have any problem rigging two n?3s in order to have 16Gb on the 4 slots? Can you confirm that I can use all the 4 slots in dual channel using the standard values? Shell I use the bios manual setting or may I just leave them all in auto? Is there any bios setting I can change to max them up without changing any voltage?

Guess that's all

Thanks in advance

[Tradesman]

The main diff beween 1-2 is the total 2 vs 4 sticks and 8 vs 16GB, and it's always best to get a full set of 16 rather than 2 of 8, even with Intel CPUs but especially with AMD due to the weaker MC. With single set you may still need extra voltage (not much) to DRAM and/or CPU/NB at 1333, going two sets would prob require more (and no guarantee the two sets will work together, though chances are good they will with more voltage)

[johnnystuff]

if I got what you saying properly it means that I can rig the ripjaws on my mobo and that's good, better if 4x4Gb rather than 2x4/8Gb. But also that probably (most likely) the default settings won't suffice in both cases (2 slots used and 4 slots used). Correct me if I'm worng please.

Anyway, here is a screenshot of my actual voltages:


can you tell me which ones should I change and most of all how much? I've been playing with bus frequencies before but never touched voltages.
Btw: is there any better guarantee that other 1333 modules will work better than those I mentioned?

[Tradesman]

The DRAM voltage (DDR voltage here) I'd start with 1.55 and the NB VID at 1.25....other sets that might work better would be F3-10666CL9Q-16GBRL and F3-10666CL9Q-16GBXL these are both CL9 sets where what you are looking at is CL7, so there would be a little less stress on the MC at CL9

[johnnystuff]

guess you mean 1.65 for dram voltage since mine is already at 1.6 anyway.... those are not terrible step up and my mobo should handle them quite well (still guessing) but I'd also read somewhere that latency on ddr3 was not that important as for ddr2, expecially using them in dual channel since there are many other factors involved in the response time. What would you suggest: "to risk" with higher voltages for a C7 or try to be happy at C9 and hopefully standard voltages (or slightly oc'd)?

[Tradesman]

Do you already have the sticks and installed? I was just looking to the settings available to clarify which to set. Latency still has a large effect on DDR3, but the throughput of DDR3 is much faster than DDR2 so some think it's not as much. Can run benchmarks on same sticks at say CL7 and CL8 or CL9 to see diffs

[johnnystuff]

no I don't have them yet, those voltages are referring to my actual 4Gb gskill something C7. In fact my main question was if they would have fit on my mobo or no chance at all since vendor lists and specs are far from being complete or trustable.
From what you say I think there is no incompatibility issue so I'll get them soon (buy tomorrow then wait for shipping time) and make them work somehow. Please let me know if there is a chance or more that they won't work at all.

[Tradesman]

I'd be more comfortable going with the CL9 sets...can't really guarantee it with AMD, they should work, but as said might take some tweaking....GSkill should be in later and might have firm info on the combo, will drop them a line for opinion and or data

[GSKILL TECH]

CL7 should be fine.

Thank you
GSKILL TECH

[johnnystuff]

thanks to all I'll update this topic in few days when I'll have the sticks

[Tradesman]

We'll be around

[johnnystuff]

finally I got them and I've plugged em. No memtest done, no bench no nothing. They work (all the 4 sticks!!)

but..... lil problem. Bios set in auto uses them at cas-9

I'll google which are the paramenters to change, feel free to tell me

[johnnystuff]

ok I just tried and it worked again ^^

so I changed CL, TRCD, TRP to 7 but I left TRAS at 24, dunno if it can go till 21-20.... shell I try? Forced a T1 rate too, eveything smooth and stable so far

[Tradesman]

Doesn't hurt to try, keep us informed on the progress

[johnnystuff]

everything's fine at RAS 20 too. Good job guys (also the asus ones btw)

Guess for the next couple of years I'm fine now, thanks again to the mods