I am reading up on DDR4 Ram as I prepare to once again try to push mine to the limits of my system and I am getting myself confused about some basic things. On G.Skill's site under Trident Series, I can select 32 Gig (8 Gig X 4) Dual Channel or Quad Channel, 3200 MHz tested speed, 14-14-14-34-2N and get the following part numbers.
Dual Channel - F4-3200C14Q-GTZ
Quad Channel - F4-3200C14Q-GTZSW
If I understand G.Skill's part numbering scheme, the SW at the end of the Quad Channel part number indicates the color scheme of the DIMMs and nothing more. Take that away and they are the same part number. If I select them and Compare, I see the image below.
The specs are exactly the same except one says Dual Channel and one says Quad Channel. So what is the difference between these 2 sets of Ram? They have the same part number except for the suffix that I am pretty sure just indicates color. They both are 8GB x 4 DIMM kits. The reason I am looking at the 3200MHz DIMMs is that I keep reading on this forum about how they are the best ones to get and I am wondering if I made a mistake when I bought my kit.
My MOBO is an Asus X99-Deluxe II which supports Quad Channel Ram- up to 128GB DDR4 @3333. When I was selecting components, I bought a set of G.Skill F4-3333C16Q-32GTZB which I got on sale at a very good price - a bit less than F4-3200C14Q-32GTZ. If I understand how this works, per the specs, the F4-3333C16Q-32GTZB has been tested (binned) to 3333MHz which is a guaranteed higher operating frequency than the F4-3200C14Q-GTZ which has only been tested to 3200MHz.
The other very crucial difference is the 3200MHz set has published timings of 14-14-14-34-2N verses 16-18-18-38-2N for the 3333MHz set. So the 3200MHz sticks have a CAS of 14 clocks, tRCD-14, tRP-14, tRAS-14, CR-2. The 3333MHz sticks have a CAS of 16 clocks, tRCD-18, tRP-18, tRAS-38, CR-2. So they can operate at a higher clock frequency but they take 2 clocks longer for CAS, and 4 clocks longer for RAS-to-CAS, Row Precharge, and Row Active times. They both have a CR of 2N (2T).
So at 3200MHz, 1 clock cycle takes .3125ns so 14 clocks takes 4.375ns. The whole cycle (CAS, tRCD, tRP, tRAS) takes 76 clocks = 23.75ns, then 2 clocks for CR = .625ns for a total of 24.375ns.
At 3333MHz, 1 clock cycle takes .300ns so the whole cycle for 16-18-18-38 which is 90 clocks = 27.00ns, then 2 clocks for CR = .600ns for a total of 27.600ns which is 3.225ns longer than the 3200MHz DIMMs.
Now I have been (unsuccessfully) struggling to get my system which is a Haswell-E i7-5820K to even boot with the XMP settings on the DIMMs of 3333MHz 16-18-18-38-2N, let alone trying to go to 1N (1T) or tighten any of the timings. I have since read that I might as well forget trying to get a Haswell-E based system to run at with Ram at 3333MHz due to IMC limitations though I might get it to run with Ram at 3200MHz.
So, my questions are:
1 - What's the deal with the G.Skill Dual Channel verses Quad Channel part numbers, that seem to be identical, and have identical specs except that one says Dual Channel kit and one says Quad Channel kit (both are 8 Gig x 4 DIMMs)?
2 - Are my calculations of the total time in ns for each kit above correct or do I not get it?
3 - Did I blow it buying F4-3333C16Q-32GTZB with latencies of 16-18-18-38-2N instead of an F4-3200C14Q-32GTZ set with latencies of 14-14-14-34-2N? If my calculations are correct, the 3333MHz kit will take 3.225ns longer per total command cycle than the 3200MHz kit, assuming I could ever get it to run at 3333MHz.
4 - If I set the system for 3200MHz Ram clock with the F4-3333C16Q-32GTZB DIMMs, should I be able to tighten their timings to 14-14-14-34-2N which would in effect be the same as the 3200MHz kit or is the F4-3333C16Q-32GTZB kit just inherently slower due to the additional clocks required for each timing stage despite the higher maximum clock rating?
5 - And last - the F4-3200C14Q-32GTZ is currently ON SALE at a good price. Would it be worth it to go ahead and buy this kit and swap them out for what I have? Will I see better stability or enhanced performance (benchmarks aside)?
If anyone actually reads all this and can offer some advice, I would really appreciate it. Thanks in advance!!
Dual Channel - F4-3200C14Q-GTZ
Quad Channel - F4-3200C14Q-GTZSW
If I understand G.Skill's part numbering scheme, the SW at the end of the Quad Channel part number indicates the color scheme of the DIMMs and nothing more. Take that away and they are the same part number. If I select them and Compare, I see the image below.
The specs are exactly the same except one says Dual Channel and one says Quad Channel. So what is the difference between these 2 sets of Ram? They have the same part number except for the suffix that I am pretty sure just indicates color. They both are 8GB x 4 DIMM kits. The reason I am looking at the 3200MHz DIMMs is that I keep reading on this forum about how they are the best ones to get and I am wondering if I made a mistake when I bought my kit.
My MOBO is an Asus X99-Deluxe II which supports Quad Channel Ram- up to 128GB DDR4 @3333. When I was selecting components, I bought a set of G.Skill F4-3333C16Q-32GTZB which I got on sale at a very good price - a bit less than F4-3200C14Q-32GTZ. If I understand how this works, per the specs, the F4-3333C16Q-32GTZB has been tested (binned) to 3333MHz which is a guaranteed higher operating frequency than the F4-3200C14Q-GTZ which has only been tested to 3200MHz.
The other very crucial difference is the 3200MHz set has published timings of 14-14-14-34-2N verses 16-18-18-38-2N for the 3333MHz set. So the 3200MHz sticks have a CAS of 14 clocks, tRCD-14, tRP-14, tRAS-14, CR-2. The 3333MHz sticks have a CAS of 16 clocks, tRCD-18, tRP-18, tRAS-38, CR-2. So they can operate at a higher clock frequency but they take 2 clocks longer for CAS, and 4 clocks longer for RAS-to-CAS, Row Precharge, and Row Active times. They both have a CR of 2N (2T).
So at 3200MHz, 1 clock cycle takes .3125ns so 14 clocks takes 4.375ns. The whole cycle (CAS, tRCD, tRP, tRAS) takes 76 clocks = 23.75ns, then 2 clocks for CR = .625ns for a total of 24.375ns.
At 3333MHz, 1 clock cycle takes .300ns so the whole cycle for 16-18-18-38 which is 90 clocks = 27.00ns, then 2 clocks for CR = .600ns for a total of 27.600ns which is 3.225ns longer than the 3200MHz DIMMs.
Now I have been (unsuccessfully) struggling to get my system which is a Haswell-E i7-5820K to even boot with the XMP settings on the DIMMs of 3333MHz 16-18-18-38-2N, let alone trying to go to 1N (1T) or tighten any of the timings. I have since read that I might as well forget trying to get a Haswell-E based system to run at with Ram at 3333MHz due to IMC limitations though I might get it to run with Ram at 3200MHz.
So, my questions are:
1 - What's the deal with the G.Skill Dual Channel verses Quad Channel part numbers, that seem to be identical, and have identical specs except that one says Dual Channel kit and one says Quad Channel kit (both are 8 Gig x 4 DIMMs)?
2 - Are my calculations of the total time in ns for each kit above correct or do I not get it?
3 - Did I blow it buying F4-3333C16Q-32GTZB with latencies of 16-18-18-38-2N instead of an F4-3200C14Q-32GTZ set with latencies of 14-14-14-34-2N? If my calculations are correct, the 3333MHz kit will take 3.225ns longer per total command cycle than the 3200MHz kit, assuming I could ever get it to run at 3333MHz.
4 - If I set the system for 3200MHz Ram clock with the F4-3333C16Q-32GTZB DIMMs, should I be able to tighten their timings to 14-14-14-34-2N which would in effect be the same as the 3200MHz kit or is the F4-3333C16Q-32GTZB kit just inherently slower due to the additional clocks required for each timing stage despite the higher maximum clock rating?
5 - And last - the F4-3200C14Q-32GTZ is currently ON SALE at a good price. Would it be worth it to go ahead and buy this kit and swap them out for what I have? Will I see better stability or enhanced performance (benchmarks aside)?
If anyone actually reads all this and can offer some advice, I would really appreciate it. Thanks in advance!!