Hi, Is it generally better when making an overclocked system that I fill all the memory slots or half fill them? I'm thinking of building a GA-P55A-UD2 or GA-P55A-UD7 (i5-760) overclocked box and don't want to fall at the first hurdle. I need at least 8G of ram, so would 2 or 4 sticks be preferred? Many Thanks
I believe that it is better to NOT fill up all your ram slots, and i also believe that 4gb for dual channel, and 6gb for triple channel is the sweet spot for overclocking. Some bright spark will be along shortley to give you the technical reasons why
It's not so much that 4 or 6 is the sweet spot, it's the memory configuration, only one slot per channel is a high speed channel. If you fill up the other slots the board will default back to it's native speed of 1066. Thats not a problem as the CPU can be overclocked and the ram can be set independently to run at the required speed. It's a bit misleading the way people talk about the way will hold back the system. Unless your going for benchmark heaven the little bit of speed you loose will be made up for by having more band width with the ram. When alls said and done it totally depends what you are using the PC for, gaming, editing etc as to what configuration will be best for you.
On my ga-p55a-ud3 I initially had 2x2gb and then upgraded to 4x2gb I did quite a bit of benchmarking with just 4gb and then 8gb. The i5-760 is over clocked with the memory running at 1520mhz. It wasn't any harder to over clock with the increase in memory from 2-4 sticks, I had already hit 4ghz on the cpu, just put the 2 new sticks in and turned it on, no problems. All the tests I did I ran 3 times and averaged, these tests were done with the cpu at 3.36ghz so the bclck was at 160 allowing the memory to run at 1600mhz. Sisoft; Memory bandwidth. 4gb; 19.41Gb/s. 8gb; 19.55Gb/s. (I thought it would make much more of a difference here) Latecny (ns). 4gb; 69. 8gb; 73. Cache+memory score; 4gb; 70.63. 8gb; 71. I have since reduced the ram timings and the latency is down to 68ns CPC benchmark suite; 4gb; Image; 1332. Video; 2283. Multithreaded; 1383. Overall; 1666 8gb; Image; 1372. Video; 2230. Multithreaded; 1416. Overall; 1673 Interesting to see the video editing decrease slightly but the other two parts increase. I used 2 games that I had with in built benchmarks, These are the average fps's from the benchmarks Just cause 2; 4gb; 54.28fps. 8gb; 53.92. Dawn of war 2; 4gb 64.53. 8gb; 60.41 I don't have access to 2x4gb sticks but I think the performance would probably be the best of both parts. I feel the slow down in certain areas is due to 4 sticks and there is no issue with the actual amount of memory. I hope this helps you in your choice. I think 2x4gb would be better but slightly (maybe?) more expensive, also I was able to spread the purchase out somewhat.
Thanks for your help, very informative. You have also answered my next question, it seems that I should manage with 1600Mhz RAM at ~4Ghz.
Another factor to consider, with four sticks you're doubling your chances of one stick not wanting to play nice with your overclock. That shouldn't be a problem if you get all of the same model, but it's out there.
I believe that in order for memory to work at any kind of channel configuration you need to have the modules be exactly the same, so if you're going to tighten the latency on your memory you're going to have to tighten them all to the lowest common timings that work for all of them. The more memory modules you have the more testing you're going to have to sit there and do before you find out which module caps out at the lowest latency values that'll work for all the rest. Another thing to consider is whether your cooler hangs over into your memory slots. Some people report that their cooler's fan hangs over their memory slots, and, while this isn't a problem normally because the channel slots in their mobo are often not affected, you might have trouble filling up every slot if your cpu cooler gets in the way. If you're using a dual channel capable CPU (not an i7) then you probably want 2x4GB.
Well put. Just needs a little clarification on the "exactly". The timings and frequency will need to be the same, but the physical modules shouldn't need to be the same brand/model, they'll just run at the speed of the slowest, as you say. Buying the same brand/model typically gives you a closer range on the limits of the modules, though. This is more for people who are looking to expand their capacity at a later date and are worried about perfectly identical modules, but it's useful to clear up just in case.
You brought up a good point there with the ram/cpu cooler height, I specifically went with the xms3 because of its low profile after seeing friends have issues with dominator in the slots further away from the cpu and my experience of cutting a few fins off a heat sink in a previous pc. Though a cpu on a 1366 can run memory in dual channel mode its just not that common. You can also set the timings for the individual channel's separately, at least in theory on some (maybe all) 1156/1366 boards so you could have memory with different timings in each slot, though I doubt think it will work that well in reality and is probably more effort than its worth.
One other important consideration is that the more RAM modules you use, the greater the strain on the actual memory controller. I'm not sure how much of an issue that is with current chipsets, but I remember it being a huge factor in stability for 680i/780i (which had flaky memory controllers) so I can imagine it has at least some bearing even with more recent chipsets too.
What is the point buying x58 triple channel slot board if your only using 1 slot? Fill them all up just get 2000mhz you should have np
You're missing the point in a couple of ways. The OP is planning a build around one of two boards that are dual-channel P55 boards with 4 slots. Secondly, the OP isn't talking about only using one module, but about whether to use one channel or to fill the board. And "Fill them all up just get 2000mhz you should have np" really isn't sound or useful advice for anyone, least of all someone who's asking for a more detailed answer.
