Trying to reach full speeds with DDR-1600

[paulbalegend]

Hello,

I have the F3-12800CL9D-4GBRL (2x2GB DDR3-1600) in a Core2 Duo E8400. I have it overclocked totally stable at 400x9=3.6GHz.

However, I can't stably achieve memory's rated speed of 800MHz (DDR-1600). My P43 chipset / memory controller only officially supports memory speeds up to DDR-1066, and I know this is the reason. Currently, I have my memory underclocked at 533MHz (DDR-1066), so that I can achieve stability. I have tightened timings to 7-7-7-20-2T to try and make up for this limitation.

My question is twofold.

1) I can boot the system at DDR-1600 with stock timings of 9-9-9-24-2T, but it is unstable. Is increasing MCH voltage the only way to get this to be stable? I have gone all the way up to 1.25V (stock=1.10V), without achieving stability. The absolute maximum on the P43 datasheet is only like 1.21V. Even at stock voltage, the MCH heatsink was getting very, very hot, so I fitted a fan to it and temps seem OK now. To get DDR-1600, should I try increasing NB-GTLref voltage? What about FSB-VTT voltage?

2) Should I forget about trying to hit DRAM frequency of 800MHz (DDR-1600) stably? If stuck at DDR-1066, what would be the tightest possible timings I could use with this RAM?

Thanks in advance,
Paul

[wevsspot]

Personally, I'd settle on a healthy cpu overclock (cpu clocks are king) and set your memory speed to whatever is required to squeeze the most performance out of your cpu. It looks like you're there now - and no sense in pushing your northbridge voltage to insane levels (IMHO). Especially since they run so hot anyway.

Regarding your timings - the only way to know is to reduce and test. Generally the first two timings are the most sensitive and also yield the best performance increases if you can lower them.

[GSKILL TECH]

Did you overclock CPU FSB to 1600MHz? If you leave it at default (333) DDR3-1333, the memory can only be that high as well..

Once you do that it should support this memory without a problem.

Thank you
GSKILL TECH

[paulbalegend]

Did you overclock CPU FSB to 1600MHz?
GSKILL TECH

Yes, I did overclock the FSB to 1600MHz. However, if I have the CPU FSB at 1333MHz, and the RAM at 1333MHz, the system will be unstable. The instability comes from the RAM speed, not the CPU speed. I can get CPU to 3.9GHz stably, as long as I have RAM frequency low, like less than 1100MHz.

[wevsspot]

Paul,

What brand and model motherboard are you running?

[paulbalegend]

Personally, I'd settle on a healthy cpu overclock (cpu clocks are king) and set your memory speed to whatever is required to squeeze the most performance out of your cpu. It looks like you're there now - and no sense in pushing your northbridge voltage to insane levels (IMHO). Especially since they run so hot anyway.

Regarding your timings - the only way to know is to reduce and test. Generally the first two timings are the most sensitive and also yield the best performance increases if you can lower them.

I think you're right. It doesn't seem like the memory speed is making much, if any, performance difference with this CPU anyway. Instead, I'm lowering FSB:RAM to have RAM below roughly DDR-1100, and getting the most clock speed out of my CPU. I hit a wall at FSB=417MHz, and nothing I did would get more speed out of it. Then, I read somewhere that changing PCI-E freq from 100 to 104MHz might help. I tried it, and sure enough, I can get FSB up to 435MHz (x9=3.9GHz) easily now! How cool is that?!? Not sure why PCI-E freq matters though.

Ironic, isn't it, that this is the way the conversation is going, on a RAM forum. But the RAM rocks, even though I can't get 1600MHz out of it. I like that it is versatile enough to operate at DDR-1600 w/ 9-9-9-24, DDR-1333 w/ 7-7-7-20, and I'm sure I can get lower latencies at DDR-1066. I've since purchased several more GSkill DIMMs for friends' builds.

It would be really cool if when they released a set of DIMMs they would publish stock RAS/CAS timings for not only the highest clock at which the sticks are rated, but lower clocks, too, like in this case DDR-1333 and DDR-1066. You have to find them out yourself, which I assume is very time consuming.

Once I settle on a CPU OC, I'll do as you suggest and start playing with timings. But I imagine I'll get bored and revert to the last proven stable settings.

[paulbalegend]

what brand and model motherboard are you running?

msi p43-c51.

[wevsspot]

Sounds like a good plan. Man, some of us have had this same argument for years now dating back to Socket A and and NF2 days

Time and time again it's been proven that for the majority of users and day to day applications that cpu clocks are king. That's one of the great things about a versatile kit of RAM. It really helps when your trying to get the most out of your FSB/BCLK/HT etc and your CPU clocks.

Glad that you've got a stable set up.

Right all of your current settings down and put them in a safe place. Then you can mess around with all of this crap again when you get bored

[paulbalegend]

Thanks, wevsspot. Your advice was helpful for sure. I have been writing the settings down.

Being new to overclocking, I'm wondering why I am finding it entertaining, since these small frequency changes don't yield nearly as much performance increase as better hardware. Nevertheless, for some unknown reason, trying to squeeze the most out of the system is definitely proving fun.

[wevsspot]

Good morning Paul. Overclocking is definitely fun Whether you're doing it as a hobby or just trying to squeeze a little more peformance out of your hard earned dollar.

In the old days overclocking could provide real world benefits even in day to day tasks. These days, with modern systems (motherboards, multicore processors, high speed memory, fast hard drives/ssd etc.) the speed increases aren't as noticeable because most of our computers are fast enough at stock settings to do everything we want to do on a daily basis.

But that certainly doesn't detract from the fun factor of overclocking just because we can!