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RAM speed and capacity, explained properly

What DDR5 speeds actually mean, why 6000 MT/s CL30 is the default for a gaming build, how to compare two kits with different speeds and latencies, and why capacity matters more than either.

The short version

32 GB, two sticks, DDR5-6000 with a CAS latency of 30, and turn the EXPO or XMP profile on in the BIOS. That covers almost every gaming build correctly.

Memory is the component most often bought on the wrong number. The big figure on the box is a transfer rate, the small figure next to it is a latency, and the two only mean something together. Buying the higher first number can genuinely make a machine slower.

Worse, a large share of machines in the wild are running their memory at a default speed well below what was paid for, because nobody turned the profile on in the BIOS. That is a free upgrade sitting inside a lot of PCs right now.

How to pick

Answer these, in this order.

Each question narrows the field. By the last one there is usually only one sensible answer left, and it is often cheaper than where you started.

  1. How much do you need?

    32 GB. 16 GB is now the number that causes stutter in demanding titles with a browser and a chat client open, and 32 GB kits are inexpensive. Only go to 64 GB if you have a specific workload that needs it.

  2. How many sticks?

    Two. Always two, in the correct slots, which on most boards are the second and fourth from the processor. Four DDR5 sticks force the memory controller to run at a lower speed, which costs you more than the extra capacity gains.

  3. What speed?

    6000 MT/s on an AMD build. That is where the memory clock and the memory controller run in step. Faster kits often break that ratio and end up slower in games despite the bigger number.

  4. What latency?

    CL30 at 6000. Use the formula in the section below to compare any two kits honestly rather than trusting the headline number.

  5. Did you turn the profile on?

    Enable EXPO on an AMD board, or XMP on an Intel one, in the BIOS. Without it your expensive kit runs at a slow default, which is the most common invisible performance bug we find in machines people bring us.

The ladder

Memory kits by tier, top to bottom.

Every tier here is a real answer for a real person. Lineup reviewed September 2026. Prices shown are launch MSRP, which is a fixed fact. Street prices move, so every product links to a live search.

Enthusiast

64 GB, for a machine with a second job

Overkill for games alone, exactly right for large project files, virtual machines, or heavy multitasking alongside a game.

Who it is for
High refresh at 1440p, or a serious run at 4K, with headroom to spare.
The tradeoff
Most of the halo experience for a meaningful discount, and the tier where power draw and cooling start to drive the rest of the build.

Various

DDR5-6400 CL32, 64 GB kit (2x32 GB)

Enthusiast

Capacity for a machine with a second job. Sixty-four gigabytes is overkill for games alone and exactly right for large scenes, virtual machines, or a browser habit that has got out of hand alongside a game.

Best for
Streaming, editing, 3D work, or development on the same machine you play on.
Watch out
Higher capacity per stick is harder on the memory controller. Check your motherboard's tested memory list before buying a fast 64 GB kit, and expect to enable the profile manually.
Speed
6400 MT/s
Latency
CL32
Capacity
64 GB (2 x 32 GB)
Profile
EXPO or XMP
Midrange

32 GB at 6000 CL30, the default

The right answer for essentially every current gaming build, and the speed and latency combination that lines up with how the memory controller wants to run.

Who it is for
The sweet spot. High refresh 1440p, comfortable 1080p, workable 4K with upscaling.
The tradeoff
The best frames per dollar most years. Long-tail owners upgrade here again in three or four years rather than never.

Various

DDR5-6000 CL30, 32 GB kit (2x16 GB)

Midrange

The default answer for an AM5 build and the reason is not marketing. 6000 MT/s with a CAS latency of 30 is the point where the memory clock and AMD's internal fabric clock line up one to one, which is worth real frames over a nominally faster kit that breaks that ratio.

Best for
Essentially every current Ryzen gaming build.
Watch out
Buy one kit of two sticks, not two kits of one. Four sticks on DDR5 forces the memory controller to run slower, which undoes the whole point.
Speed
6000 MT/s
Latency
CL30
Capacity
32 GB (2 x 16 GB)
Profile
EXPO for AMD, XMP for Intel
Value

32 GB at a slower speed

Keeps the capacity, saves the money, gives up a few percent. In a build with a value graphics card, the card is the limit long before the memory is.

Who it is for
Solid 1080p at high refresh, 1440p if you are willing to move a slider.
The tradeoff
Buys most of the playable experience for a fraction of the top. Usually the first tier where memory capacity starts to limit longevity.

Various

DDR5-5600 CL36, 32 GB kit (2x16 GB)

Value

The budget kit that is still the right capacity. Slower than the 6000 CL30 default and cheaper, and in a build with a value graphics card the card runs out of headroom long before the memory does.

Best for
Budget builds where 32 GB matters more than the last few percent of speed.
Watch out
Do not drop to 16 GB to save money. Capacity is the axis that causes stutter and forced texture reloads. Speed is the axis that costs a few percent.
Speed
5600 MT/s
Latency
CL36
Capacity
32 GB (2 x 16 GB)
Profile
EXPO or XMP

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MT/s is not MHz, and the box is usually wrong

DDR5-6000 means 6000 megatransfers per second. It does not mean 6000 MHz, although plenty of boxes and listings print exactly that. The actual clock is 3000 MHz, and DDR memory moves data twice per clock cycle, which is where the doubling comes from. The letters DDR stand for double data rate.

This matters because it is the source of most of the confusion in memory listings. When you see a kit advertised at 6000 MHz, read it as 6000 MT/s and move on. Nobody is lying to you on purpose, the industry has just been sloppy about it for twenty years.

How to compare two kits in one line of arithmetic

The transfer rate is how much data moves per second. CAS latency, written CL, is how many clock cycles the memory waits before it starts answering. A faster kit with a worse latency can easily be slower in practice, and there is a simple way to check.

True latency in nanoseconds equals CL multiplied by 2000, divided by the transfer rate. Work that out for both kits and compare. Lower is better, and the difference is usually small enough that capacity and price should break the tie.

KitCL x 2000 / speedTrue latencyVerdict
DDR5-6000 CL3030 x 2000 / 600010.0 nsThe default. Buy this one
DDR5-6000 CL3636 x 2000 / 600012.0 nsCheaper, a few percent slower
DDR5-6400 CL3232 x 2000 / 640010.0 nsSame latency, more bandwidth
DDR5-7200 CL3636 x 2000 / 720010.0 nsSame latency, may break the 1:1 ratio
DDR5-5600 CL3636 x 2000 / 560012.9 nsFine on a budget build
Latency alone does not decide it. A kit that runs the memory controller out of step can lose more than its latency advantage gains, which is the next section.

Why 6000 is the number people keep repeating

On current AMD platforms the memory controller can run in step with the memory, one cycle for one cycle, up to roughly 6000 to 6400 MT/s. Push past that and the controller usually drops to running at half the memory rate, which adds latency to every access.

The result is that a 7200 kit can be slower in games than a 6000 kit on the same board, despite the larger number and despite identical true latency. That is the whole reason 6000 CL30 became the standing recommendation. It is not superstition, it is where the hardware stops cooperating.

On Intel platforms the ratio behaviour is different and faster kits are more often worth it. If you are on Intel, check your specific board and chip rather than borrowing the AMD rule.

Capacity beats speed, every time

Moving from a slow kit to a fast one is worth a few percent in most games. Moving from too little memory to enough is worth the difference between a game that runs and a game that hitches every time it loads new assets.

If your budget will not cover 32 GB of fast memory, buy 32 GB of slower memory. That is not a compromise, it is the correct ordering of priorities.

Next step

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