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Number crunching :
Please help me with a new machine build
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Tilmitt Send message Joined: 31 Oct 02 Posts: 9 Credit: 9,769,912 RAC: 0 |
OK, so I did a little research on dual channel RAM and it seems that one way to get a viable 24 GB solution would be: If he puts a 4Gb and 8GB stick in each channel there's no problem here. 12GB in each channel. I've seen people make the claim that it's not a good idea to mix different sticks in the same channel but I've never seen any evidence that this causes problems. Also even if he did it "wrong" and put the two 8GB sticks in the first channel slots and the two 4GB sticks in the second channel slot it would operate in flex mode and he would get dual channel for the first 8GB in each channel and then single channel speed for the final 8GB in the first channel. http://www.intel.com/content/www/us/en/support/boards-and-kits/000005657.html#flex |
Stephen "Heretic" Send message Joined: 20 Sep 12 Posts: 5557 Credit: 192,787,363 RAC: 628 |
OK, so I did a little research on dual channel RAM and it seems that one way to get a viable 24 GB solution would be: . . That's the way I understand it, but it's important to make sure the RAM is all coherent, ie same speed and latency and preferably same manufacturer. Those all seem to be suitable. Stephen :) |
Stephen "Heretic" Send message Joined: 20 Sep 12 Posts: 5557 Credit: 192,787,363 RAC: 628 |
OK, so I did a little research on dual channel RAM and it seems that one way to get a viable 24 GB solution would be: . . Sorry but that is not the way I understand it (see diagram). Same all round is fine, but his way works AOK. In my Core2 Duo I have 2 x 2Gb and 2 x 1GB and running just fine thank you very much. The most critical consideration is that each bank has totally coherent ram, same size, same speed, same latency, preferably same manufacturer. But the next priority is to have the same speed and latency across all banks. Chan 0 Chan 1 Bank 0 _________ _________ | | | | Slot 0 |__8GB____| Slot 2 |__8 GB___| Bank 1 _________ _________ | | | | Slot1 |__4GB____| Slot 3 |__4 GB___| 12 GB 12 GB |
HAL9000 Send message Joined: 11 Sep 99 Posts: 6534 Credit: 196,805,888 RAC: 57 |
OK, so I did a little research on dual channel RAM and it seems that one way to get a viable 24 GB solution would be: The same article shows configuration for best performance under Dual-channel with four DIMMs. Where the first group is populated with one size and the second group is populated with another size. In Intel's example they used a pair of 4GB and 2GB DIMMs for 12GB. My personal preference would be to go with 32GB (2x16GB DDR4-2400). That leaves the system open to be maxed at 64GB later if need be. Going with 4x8GB could be more a more cost effective way to run DDR4-2400 over DDR4-2133. For the CPU cooler the stock Intel ones are not ideal for 24/7 crunching. The environment the machine operates in is really the deciding factor. The cooler can always be upgraded later if required. SETI@home classic workunits: 93,865 CPU time: 863,447 hours Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[ |
Stephen "Heretic" Send message Joined: 20 Sep 12 Posts: 5557 Credit: 192,787,363 RAC: 628 |
Yes, and another one at x4. According to a graph in this article, there is no substantial downside to running a GTX 680 in a PCIe 3.0 x4 slot: . . That would be true if the PCIe bus were to be driven at anything near full capacity. Crunching only uses a small fraction of the bus capacity, and I doubt you would be able to even measure any difference in productivity between the two. . . I have 2 x GTX1060s running in two PCIe 1.1 slots at x 8, and they barely make a blip on the bus usage, lurking down about the 10 to 12% area. Stephen :) |
HAL9000 Send message Joined: 11 Sep 99 Posts: 6534 Credit: 196,805,888 RAC: 57 |
OK, so I did a little research on dual channel RAM and it seems that one way to get a viable 24 GB solution would be: I would have modified the diagram slightly with the labels Bank0 = 16GB Bank1 = 8GB Since it is less common to provide a total for each channel. SETI@home classic workunits: 93,865 CPU time: 863,447 hours Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[ |
Wiggo Send message Joined: 24 Jan 00 Posts: 36871 Credit: 261,360,520 RAC: 489 |
Yes, and another one at x4. According to a graph in this article, there is no substantial downside to running a GTX 680 in a PCIe 3.0 x4 slot: Over the years of using multi GPU's on x16, x8 and x4 PCI-e slots I have never seen any differences in crunching times between them, gaming is a totally different story to crunching SETI. Cheers. |
Zalster Send message Joined: 27 May 99 Posts: 5517 Credit: 528,817,460 RAC: 242 |
Actually, I have seen the difference. The problem, or rather the solution, is that we have really good optimized apps here at Seti (tips hat to the developers) On other projects where the apps aren't as well optimized, you can see a huge difference in processing data depending on the PCI-e speed. |
Zalster Send message Joined: 27 May 99 Posts: 5517 Credit: 528,817,460 RAC: 242 |
Is this on your Linux system? If so, aren't you only running 1 at a time? I only ask as windows users tend to run more than 1 at a time and the tuning can increase that FB usage. I mention this as one of my teammates spend alot time finding the tuning commonly used now. We are off topic again, apologies to the OP. |
Brent Norman Send message Joined: 1 Dec 99 Posts: 2786 Credit: 685,657,289 RAC: 835 |
... and occasional HD or even 4K video editingI would look at the specs for this to answer your 24/32MB question. That is where you will want more memory IMO. |
rob smith Send message Joined: 7 Mar 03 Posts: 22540 Credit: 416,307,556 RAC: 380 |
Running the Perti/Tbar special app you only run one at a time. It is designed to use all available to core to the max, unlike the SoG and older offerings which only use the number of cores needed and that is often below 50% - hence running two at a time under Windows or Linux when running older apps. Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
Helsionium Send message Joined: 24 Dec 06 Posts: 156 Credit: 86,214,817 RAC: 43 |
Thank you all for your answers. Based on your answers, I chose the following options: MB, CPU, GPU as posted intially The € 35 CPU fan (designed for up to 140W TDP) 16 GB of DDR4-2400 RAM. If I need more, I can upgrade to 24 or 32 GB later. |
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