I had good results (R10) with crucial. BL16G32C16U4W.M16FE1  64GB . 2x 32GB kits  (4x 16GB modules)These are dual rank (M16FE1) . Passes all the tests even after several bios updates

What speed can you run them at? Are they th ballistix?

This is what I have and it works fine.  I have it running at a stable 3466mhz with the XMP-3200 Timings at 1.35v. These are crucial ballistx 3200mhz 2x16GB kit.  I have tried running them at 3600mhz but my R10 does not like it.

What R10 do you have? There are 2 different versions of the R10. 1 with Ryzen 3000 CPU, one with Ryzen 5000 CPU.

I have the gen 1 r10 with the ryzen 3000 cpu. I'm hoping that dell will at some point release a bios update to allow for a ryzen 5000 cpu, but i'm not holding my breath.

Those are the ballistix running xmp @3200 mhz. I have the gen1 r10 The crucial site has only two choices Ryzen Ed. and Ryzen Ed. R10. They both list the same one .

https://www.crucial.com/upgrades/alienware/alienware-desktops

I had the original Dell one's (32GB). (I tried one set Dell and crucial that worked well , then  I bought another crucial set and removed the Dell set.)So far no trouble.Now all 4 modules are the same.

I did try a pair a HyperX  XMP 3200 with the Dell pair (different speed,latency etc.) that worked for a while ,it did pass the pre-boot memory diagnostics but failed with other memory tests after bios upgrade.

In case of doubt just run the crucial scanner to confirm.

They will not release a BIOS update to support Ryzen 5000 on that platform.

As for the memory, up to XMP 3200 is supported on that platform. There is a thread on this board somewhere that provides some information from other users on what works and what does not. 

These systems offer very limited support for aftermarket memory modules. The only ones to be guaranteed to work are the OEM modules listed in the FAQ: R10 FAQ 

Only up to the 3200 modules work in the R10 Ryzen 3000.

Ryzen 7 5800(no x)

100% compatible and functional.

The Aurora R10 specifications are a Ryzen 7 5800(no x), RX6800XT, 1000w PSU, and 1 stick of 3466MHz ram. I am planning to sell the one stick and upgrade to dual channel, but now I’m not sure what RAM kit to buy? Generous fellows have confirmed that Crucial Ballistix gaming RAM would be compatible, but the price on that kit is just too high for my liking. Corsair LPX vengeance(2x8GB 3200MHz) on Amazon is going for a pretty low price. I was just wondering If any of you had compatibility with that in the Aurora R10. Thanks again. 

These systems are very picky when it comes to aftermarket memory support. Even if it works on one BIOS, the next BIOS update might break that compatibility.

So be very careful what you pick and always pick what has been known to work for others, to avoid headaches.

The only memory to guaranteed work is the OEM validated memory and the part #'s can be found in the R10 FAQ.R10 FAQ 

Your R10 supports up to 3,400 Mhz, and since Ryzen likes faster memory speeds I would opt for that rather then 3,200 Mhz, if the timings are the same. If the timings are not the same you have to do a calculation to figure out which kit is actually faster.

If you are going the aftermarket route ensure to purchase Dual kits only. Don't purchase 2 single sticks, always kits.

Alienware Aurora R10 (Ryzen 9 5900) – Manual RAM Configuration Findings

System

Model: Alienware Aurora R10

CPU: AMD Ryzen 9 5900 (Zen 3)

BIOS: Alienware 2.2.4

Memory: Corsair Vengeance LPX 32 GB (2×16 GB)

DDR4-3200

Timings: CL16-20-20-38

Voltage: 1.35 V

Model: CMK32GX4M2E3200C16

Background

After installing the Corsair kit, the system defaulted to JEDEC 2133 MT/s, as expected on the Aurora R10 where XMP is locked for non-Dell OEM memory. XMP could not be enabled in BIOS.

I therefore attempted manual memory configuration using the Alienware BIOS, which requires hexadecimal timing values.

Attempt 1 — DDR4-3200 (1600 MHz real clock)

BIOS settings:

Memory Frequency: 1600
DRAM Voltage:     1.35 V

tCL (Tcl):        10
tRCDRD:           14
tRCDWR:           14
tRP:              14
tRAS:             26

(Hex values corresponding to 16-20-20-20-38 in decimal)

Result:

System successfully booted

Windows reported 3200 MT/s

Stable throughout the day (gaming, normal use)

Issue:

After a true cold boot the following day, the system struggled to POST

BIOS reverted memory to 2133 MT/s

Manual 3200 settings could no longer be reliably retrained

This suggests insufficient cold-boot training margin at the 3200 strap on this BIOS.

Attempt 2 — DDR4-2933 (1466 MHz real clock)

To improve cold-boot stability, I tested a lower memory strap.

BIOS settings:

Memory Frequency: 1466   (DDR4-2933)
DRAM Voltage:     1.35 V

tCL (Tcl):        10
tRCDRD:           14
tRCDWR:           14
tRP:              14
tRAS:             26

(Same timings, lower frequency)

Result:

System booted normally

Memory speed reported correctly as 2933 MT/s

Passed:

Cold reboot

Overnight power-off / next-day boot

No further fallback to 2133 MT/s observed

Conclusion

On Alienware Aurora R10 (BIOS 2.2.4) with non-Dell DDR4-3200 memory:

Manual DDR4-3200 (1600 MHz) can work temporarily but may fail cold-boot training

DDR4-2933 (1466 MHz) provides significantly better training margin and long-term stability

Gaming performance difference between 2933 and 3200 is negligible, while stability is greatly improved

For users experiencing repeated memory speed resets on cold boot, 2933 MT/s appears to be the practical “set-and-forget” ceiling on this platform.

Hope these findings can be helpful!