RAM bandwidth calculator: MT/s, channels and GB/s
Memory bandwidth is how much data your RAM can move each second. Enter the speed and the number of channels to get the theoretical peak, and see what single channel costs you.
How memory bandwidth is calculated
System memory moves data in 64-bit wide channels. Every transfer carries eight bytes, so the bandwidth of one channel is the data rate in megatransfers per second multiplied by eight, divided by a thousand to give gigabytes per second. A DDR5-6000 channel moves 48 gigabytes per second, so two channels move 96. A single DDR4-3200 channel moves 25.6, and two move 51.2.
These are theoretical peaks. Real throughput is lower because of refresh cycles, access patterns and the memory controller, but the relative figures hold: doubling the channels or the speed doubles the peak.
Bandwidth by speed and channels
Theoretical peaks for common memory speeds. Real-world throughput is lower.
| Speed | Single channel | Dual channel | Quad channel |
|---|---|---|---|
| 3200 MT/s | 25.6 GB/s | 51.2 GB/s | 102.4 GB/s |
| 4800 MT/s | 38.4 GB/s | 76.8 GB/s | 153.6 GB/s |
| 5600 MT/s | 44.8 GB/s | 89.6 GB/s | 179.2 GB/s |
| 6000 MT/s | 48.0 GB/s | 96.0 GB/s | 192.0 GB/s |
| 7200 MT/s | 57.6 GB/s | 115.2 GB/s | 230.4 GB/s |
Why dual channel matters
Running one stick means one channel. Running two matching sticks in the right slots usually gives two channels and double the bandwidth. For discrete graphics cards the difference in games is often modest, but it can be several percent in processor-limited games and much more for integrated graphics, which use system memory as video memory. If your PC has a single stick, adding a second matching one is one of the cheapest upgrades available.
Check your motherboard manual for the recommended slots. Two sticks in the wrong slots can still run single channel. A kit sold as a pair is the safest choice because the sticks are matched.
Bandwidth, latency and capacity together
Good memory is a balance of three things: capacity, bandwidth and latency. Capacity decides whether your games and apps fit without swapping to disk. Bandwidth decides how quickly data flows. Latency decides how quickly each request is answered. Chasing one figure alone can waste money, so decide your capacity first, then pick the fastest kit your platform supports at a sensible price.
Use the RAM for gaming calculator for capacity and the RAM latency calculator for responsiveness. Our processor and memory bottleneck guide explains when memory limits a fast graphics card.
How to use the rAM bandwidth calculator
- Read the speed on the kit label. If it says DDR5-6000, enter 6000 and choose MT/s.
- If you only know the real clock in MHz, choose MHz and the tool doubles it.
- Choose how many memory channels you are using.
- Read the bandwidth and compare with another setup by changing the channels.
- Use the latency tool alongside it to judge a kit properly.
Common mistakes to avoid
- Mixing up MHz and MT/s. DDR runs at twice its real clock.
- Installing two sticks in the wrong slots so they run single channel.
- Treating theoretical peak as real speed. Actual throughput is lower.
Related tools and guides
Keep going with these: RAM latency calculator, RAM for gaming calculator, CPU and GPU bottleneck checker, GPU memory bandwidth calculator, processor and memory bottleneck guide.
Frequently asked questions
How do you calculate RAM bandwidth?
Multiply the data rate in MT/s by eight bytes and by the number of channels, then divide by a thousand for gigabytes per second. DDR5-6000 in dual channel gives 6,000 times 8 times 2 divided by 1,000, which is 96 gigabytes per second.
Is dual channel RAM worth it?
Yes. It doubles peak bandwidth for a small cost and helps games in processor-limited scenes, and much more with integrated graphics. Two matching sticks are usually cheaper and more reliable than one large stick, and they make the memory controller work better.
What is the difference between DDR4 and DDR5 bandwidth?
DDR5 runs at much higher data rates, so a typical dual-channel DDR5 kit moves around 90 to 100 gigabytes per second against about 50 for DDR4-3200. Latency stays in a similar range, so the gain shows most in bandwidth-hungry work.
How do I check my RAM is running in dual channel?
Use a system information tool that shows the channel count, or check that your sticks are in the slots your motherboard manual recommends. Many tools report single or dual channel directly. Two sticks in the wrong slots can still run as single channel.
Does RAM bandwidth affect FPS?
Only when it is the limit. Discrete graphics cards use their own fast memory, so system RAM matters less. It helps most in processor-limited games and with integrated graphics. For most gaming builds, capacity and dual channel matter more than the last bit of speed.
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