In this third and final installment of our deep dive into memory and RAM, we are going to look at dual-sided and single-sided memory sticks and see why not all sticks are created equal. Here are some links in case you didn’t read the first and second parts of this series.
Ranks
Memory sticks can be single rank (single-sided) or dual rank (dual-sided). Which you choose can have a noticeable impact on overclocking and a slight impact on performance.
Dual rank can offer a bit better performance. A 3000 MHz dual rank module should marginally outperform a 3000 MHz single rank module. However, single-rank modules usually overclock a bit better. Of course, if you aren’t running benchmarks like Super PI for HWBot competitions, you shouldn’t be overly concerned with performance. The most important consideration here is that dual rank modules put significantly more strain on the IMC.
A memory support chart for the first Ryzen CPUs; it makes a huge difference whether four sticks or two are used and if they are single or dual ranked
Also if you put memory in every RAM slot it also puts more strain on the IMC. And more strain on IMC equals worse maximum RAM clocks.
Regardless the platform, if you want to populate all the memory slots on your motherboard and to overclock, you’d be best advised to use single-sided sticks.
This feature is easy to inspect visually – dual-rank sticks have memory modules on both sides of the PCB. Conveniently as well, the CPU-Z reports your memory’s rank (check SPD tab).
A dual rank module reported by CPU-Z
Tip: Look closely at CPU manufacturers’ specifications. Maximum supported RAM clocks for Ryzen 3000 CPUs are given for two sticks of single-sided memory (clock-wise it is the best possible scenario).
Good to know: Technically, sides and ranks aren’t the same thing – dual-sided RAM can be single rank and there are also quad rank modules. But in today’s world of consumer-grade memories, it is virtually the same, so I took the liberty of making this simplification. If you want to know more about the topic, watch these videos, which complement each other nicely:
All you need is B-Die
Consumer RAM sticks are basically made of PCBs and ICs (RAM chips). Those parts contribute to quality of the memory, mainly its overclocking potential. There is also an SPD chip, but this part can be reprogrammed if you know what you’re doing.
With DDR4, the main IC suppliers are Micron, Hynix and Samsung.
Basically, Samsung B-Die ICs are the best for overclocking—and that’s all there is to it.
DDR3, on the other hand, isn’t so simple. There was a far larger variety of ICs and what they were good at/for. The list below attests well to the range:
Micron D9 GTS / Micron D9 GTR – rather low max clocks but great timings. They require high voltages. Good for LGA 775.
A stick will have 1 or 2 GB capacity, though 2 GB sticks are relatively rare.
Elpida BBSE – A good choice for LGA 1156, LGA 1155, LGA 1150, LGA 1366 and AM3(+). Capable of fairly high clocks but not great at tight timings. It likes high voltages.
1 GB or 2 GB capacity (per stick). The 1 GB is single-sided.
G.Skill Perfect Storm DDR3 based on Elpida BBSE chips
Elpida Hyper MNH-E / Elpida Hyper MGH-E – A great choice for LGA 1156, LGA 1366, Sandy Bridge and AM3(+). It offers a good balance between high clocks and tight timings. They don’t scale well with voltage.
1 GB or 2 GB capacity per stick. The 1 GB is single-sided.
Corsair Dominator GTX2 - one of the most famous DDR3 memories, based on Elpida MGH-E chips. Notice that the heat spreader is much higher than in the standard Dominator GT series. GTX were handpicked sticks for true enthusiasts, so it’s a pity that Corsair isn’t following this great legacy.
PSC X (PowerChip X rev.) / Elpida BDBG are made for high clocks with acceptable timings. They perform very well with Ivy Bridge, LGA 1150, LGA 2011, AM3(+), FM2(+).
1 GB or 2 GB capacity per stick. The 1 GB is single-sided.
Mach Xtreme ArmorX DDR3 based on PSC X chips
Hynix CFR / Hynix MFR / Hynix BFR – offers loose timings but very high clocks. Performance can be poor, especially in single-sided modules. Work best with the LGA 1150.
2 GB or 4 GB capacity per CFR/BFR stick. The 2 GB is single-sided.
4 GB or 8 GB capacity per MFR stick. The 4 GB is single-sided.
Samsung HCH9 offers great performance and scales well with voltages. Good for Ivy Bridge, LGA 1150 and LGA 2011. They are also great for day-to day usage, because of the higher capacities than other OC-oriented memories.
4 GB or 8 GB capacity per stick. The 4 GB can be single- or dual-sided. The 8 GB is always dual-sided.
This list of DDR3 ICs is by no means exhaustive. I’ve listed only those that are good for certain overclocking applications.
If you are looking for sticks with certain IC modules, look for lists like this one:
ECC & Registered / Buffered
When looking for RAM, you surely must have stumbled across ECC type memory and registered / unregistered / buffered / unbuffered modules.
Unregistered (unbuffered) RAM without ECC is a typical consumer-grade product. ECC and / or registered memory is a server / professional workstation solution and requires support from a memory controller.
ECC means that each module features a special chip that checks for data errors. This task decreases performance a bit.
Registered (buffered) memory features a register that buffers data traveling between the RAM modules and the memory controller. It results in higher latency than in unbuffered memory. But buffering increases the reliability of data access and allows for the use of huge RAM capacities in single system.
ECC feature and registered feature are two different things. Memory can feature one or both of these functions simultaneously.
Overclocking
Samsung B-Die-based sticks get the job done best, and usually scale well with voltage (even beyond 2,0 V). Sadly, they are entering end-of-life (EOL) status. For all ambient cooling solutions, I wouldn’t recommend going above 1,5 VDIMM for the sake of your IMC’s lifespan. Manufacturers say that doing so is dangerous for the CPU. But running around 1,4 VDIMM should be totally safe for 24/7 use. Actually, 1,5 V is the maximum voltage permitted for implementation in an XMP profile.
Finally, don’t be fooled by motherboard manufacturer marketing on phase count. Because DDR4 memories consume so little power, the phase count of memory power delivery on a motherboard isn’t all that important.
Problem solving
Platforms with more than two DDR channels, especially older ones like the LGA 1366 and LGA 2011, can suffer from not recognizing all of the RAM installed. Most of the time, the solution to this problem is to take the CPU out of the socket and remount it rather than reinstalling the memory sticks.
Populating all DIMM slots on the motherboard (especially on the quad channel systems) can lead to RAM clock problems. However, giving the IMC more voltage can help – depending on the platform, try raising the System Agent voltage slightly (be warned that going too far can easily destroy your CPU).
The extremely rare Crucial “French Edition” DDR2
Part III Takeaway
- If you plan to populate all DIMM slots on the motherboard, memory ranks may prove more important than you think.
- Average users shouldn’t bother with ECC and buffered memory kits.
- For serious HWBot overclocking, memory based on proper ICs must be chosen. For normal usage, though, it isn’t all that important.
