Review on HyperX Predator Black 2400MHz HX424C12PB3 by Stephen Burgstaller

I've had one of these for a year (2 x 8GB in RGB variant) running at 3200MHz on a Ryzen 2700X with an MSI B450 Pro Carbon. They have a default auto speed of 2400MHz and two XMP profiles of 2933MHz and 3200MHz. Recently (a year later) I added another one of 32GB, the machine doesn't boot at 3200Mhz with 32GB, not even POST. Swapped sticks, tried all combinations, it worked with some others. The new sticks in slots A1/B1 and the old ones in A2/B2 offer the highest speeds. 4 sticks worked fine at 2400MHz in any slot configuration. On one it worked at a frequency of up to 2666MHz, and on the other two it flashed at 3200 but was unstable. In the worst slot configurations, none of the XMP profiles worked. At best, all configurations worked, but only 2993 MHz was stable. When attempting to set custom timings I discovered (using Thaiphoon's recording software) that two kits (of the same model, purchased a year apart) were actually made two years apart and had different RAM chips. In other words, they were incompatible. Any combination of two sticks (from old and/or new sets) will work fine at 3200MHz, but not all four. Ryzen inter-core cluster CCX speeds depend on RAM speed, which means lower RAM speeds. some core to core communications will be slower. This speed is typically the same as the physical RAM clock speed (half the frequency of DDR). However, the maximum rated speed of 2000s Ryzen desktop RAM is 2993MHz, and anything above that is overclocking. For a 4-bar configuration, AMD officially only guarantees 2133 MHz. It is currently clocked at 2933MHz via the XMP profile, and performance in high CPU tests like Cinebench R15 is about 99.8% from 16GB 3200MHz. However, the speed is much faster in apps like Photoshop and Audacity: both apps launch almost instantly and run like greased lightning, and the Unreal Engine 4 doesn't slow down after a while, especially after a few undos. So the real world performance is much better for me at least. The moral of the story is that when multiple RAM kits are paired together (even of the same make and model) they should probably be purchased at the same time from the same vendor to ensure the internals match and they are rated at their maximum can run speeds.