the ram upgrade was on the orphan Dell GX280 my daughter left here and I was using for Sentinel. It has indeed worked well.
I use a Dell at work and have for some time. But my personal devices are all Apple; MacBook Pro, MacBook Air, iPad and iPhone. That's why I was a little hesitant about cracking open the Dell. But having done memory before on Mac laptops, this was a walk in the park. I could actually see and reach everything, and without any tools at all. Very easy upgrade, and cheap, too, for that matter.
As an aside, and I know this is a bit off-topic now, but I thought it might be of interest ... I initialized a spare 32gb sd card using Sentinel (now that it is working), set it up as for the HP, swapped it in in place of the stock card, and it seemed to work just fine. I don't know if it would actually have the ability to access the additional memory space or for that matter, if it could ever need that much space, but it does appear that it is possible to use a larger card than the one that comes with the receiver. This may already be documented elsewhere in these discussions, and I haven't bothered looking for that (still!) but it was a fun and interesting experiment.
Still regret I can't just run Sentinel easily on my Mac. that would be much more convenient.