Ram Problems

🧠 Why Your RAM Isn’t Running at Full Speed

A simple guide from Peterborough Custom Computers

Modern RAM (DDR4) is often sold as 2666 MHz, 3000 MHz, 3200 MHz, or higher, but most PCs do not run at these speeds by default. If your system is showing 2133–2400 MHz, this is completely normal.

Here’s why — and what to do about it.

🔧 1. RAM Has Two Speeds: JEDEC and XMP/DOCP

JEDEC (Default Speed)

Every motherboard boots RAM at a safe, universal speed such as:

  • 2133 MHz
  • 2400 MHz
  • 2666 MHz

This ensures the system always starts reliably, even with brand‑new hardware.

XMP/DOCP (Advertised Speed)

The higher speed printed on the RAM box (e.g., 3000 MHz or 3200 MHz) is stored as a performance profile. To use it, you must enable:

  • XMP (Intel boards)
  • DOCP / EXPO (AMD boards)

This tells the motherboard to load the correct speed, timings, and voltage.

⚠️ 2. Why Higher Speeds Sometimes Cause Crashes

If your PC runs fine at 2400 MHz but crashes at 2666 MHz or higher, it usually means one of the following:

A. The RAM voltage is too low

Most high‑speed RAM needs 1.35 V, but many systems stay at 1.20 V unless manually set.

B. The memory controller (inside the CPU) is struggling

Every CPU is slightly different. Some chips handle high speeds easily; others prefer lower speeds.

C. The RAM sticks are mismatched

Different brands, sizes, or speeds can limit stability.

D. The motherboard BIOS needs updating

Older BIOS versions can have poor memory compatibility.

E. Timings are too tight

Some RAM kits use aggressive timings that certain boards can’t handle.

🛠️ 3. How We Fix It

At Peterborough Custom Computers, we check:

  • Correct DRAM voltage
  • Safe SoC voltage (for AMD systems)
  • Stable timings
  • BIOS version
  • Whether the RAM kit is compatible with your motherboard
  • Whether the memory controller is the limiting factor

We then tune the system for the highest stable speed, not just the advertised one.

✔️ 4. What You Can Do Yourself

If you’re comfortable entering the BIOS, you can try:

  1. Enable XMP/DOCP
  2. Set DRAM Voltage to 1.35 V
  3. Try a moderate speed like 2666 MHz or 2933 MHz
  4. Update your motherboard BIOS

If the system becomes unstable, simply return to the previous stable setting.

🧩 5. When to Contact Us

Get in touch if:

  • Your PC crashes when enabling XMP
  • RAM won’t run above 2133–2400 MHz
  • You’re mixing different RAM kits
  • You want the system tuned for maximum performance
  • You’re unsure which settings are safe

We’re always happy to help diagnose and stabilise your system.