PC not booting at all with EXPO on & some issues

InfiniteNoise · 24 Sep 2023 at 18:33

So I'm trying to sort out things on a relative's computer with few issues, the components that are potentially problematic & the issues are,

Components,
- Ryzen 7900
- MSI B650i Edge board (with latest BIOS released on 15/8)
- Corsair Vengeance DDR5 RAM, 32GB (2x 16GB), 6000MHz CL36, AMD EXPO Compatible
(for the rest of the system, Corsair SF750 PSU, Radeon RX 6700)

Issues,
- won't POST/boot at all with EXPO enabled, or with it off + memory clocks higher than stock (4800MHz)
- any curve optimizer settings (even very minor negative/positive) eventually results the PC not booting after few restarts/shutdowns

When these issues occurs, the only way I can get the PC to boot again is to clear CMOS. If I leave everything on stock, it runs wonderfully without any issues, stable when stress tested, it's just that any adjustments to the CPU or RAM results in the PC not booting, and on the rare occasions it manages to get past POST, it just hangs.

CO isn't the issue, but not being able to run higher clocks for the RAM got me stumped.

Tried reseating everything and re-flashing BIOS, didn't help, I can't tell if it's one or more of those components that's a lemon (when not running at stock).

Our system is pretty much identical, except mine has 7800X3D, and their RAM in mine runs at EXPO 6000 Mhz fine, so I guess the RAM is fine.

What am I missing?

InfiniteNoise · 24 Sep 2023 at 19:38

When EXPO is on, the DRAM voltage is set to 1.350v, which seems about right? I tried setting it to 5200mhz non-EXPO with 1.350v (up from 1.1v on stock), booted but CPU runs a bit slower.

Everything at stock (4800MHz, DRAM voltage at 1.1v), the CPU scores 25500~ in CB R23 mulitcore test, which is actually a bit higher than normal.

But with RAM adjusted to 5200Mhz with voltage at 1.35v, CPU scores 24100~ in CB R23, which is about right for the CPU on stock, but that's lower than above when everything is on stock.

Looking at the CPU clock speeds when running CB R23 multicore test, 4.6GHz all core when everything is on stock, 4.4GHz all core with RAM at 5200MHz.

Not ideal but I'm getting there I guess.

Edit: also to add that I'm aware about the memory training and long boot time issue with EXPO, but even after waiting 30+ mins on couple of occasions for it to finish training with EXPO enabled, nothing happens.

InfiniteNoise · 24 Sep 2023 at 20:23

I'll have to give that a go in a moment, but if that doesn't help and it results in the PC still not booting, I'll just not bother with overclocking the memory speed and instead just tighten the timings a bit.

Yeah, won't bother with CO either, even on stock it performs decently, I'm surprised with how well it runs compared to 7900X with just almost the 1/3 the TDP.

Looks like EXPO is just annoying to deal with based on what I've seen.

InfiniteNoise · 24 Sep 2023 at 20:41

As mentioned in the initial post, the kit is Corsair Vengeance DDR5 RAM, 32GB (2x 16GB), 6000MHz CL36, AMD EXPO Compatible.

Though that same kit worked fine in my system with EXPO enabled, I'm starting to think it's the motherboard that's the issue.

InfiniteNoise · 25 Sep 2023 at 23:53

I'm aware, it just won't boot at all with EXPO enabled, I've waited 30+ mins, and since my last post here I've conducted some more tests, it's the motherboard that's the issue.

I put the CPU + RAM in my motherboard (same board, MSI B650i Edge, both on same BIOS version as well as similar settings), and they ran fine with CO + EXPO enabled without issues while they couldn't in the other board, and to rule anything else out, I tested the same CPU + RAM in another board that I borrowed (ASUS ROG Strix B650E-I) and they ran fine too.

The board is still in its return window so I'll ask them to return it and get a different board.

Update: new board arrived, EXPO works, just as I expected, the board is useless so it goes back.