Wow, the above Ebay links... or rather the prices in them, makes me want to sell all of my retro PCs right now. 😁
Seriously, anything over $50 for any of those PCs is too much. Probably only the Optiplex 3020 is a bit more reasonable, given it comes with a 240 GB SSD. But even then, you can grab similar-specced machines, sans the HDD/SSD and possibly the RAM, for usually... $20-30 locally. FWIW, I bought two Optiplex 3010 SFF machines this summer, each at $15 a pop. No RAM or HDD inside, but if I had bought the other 2 the seller had (for $60 total) the seller said he would have included RAM for them too. Now that I think about it, I probably should have grabbed them all. They each came with an i5-3570, which itself is worth close to $10 anywhere online (with the shipping included / factored in.) But that's OK, because there was another Craigslister near me selling DDR3 RAM for approx. $1.25/GB (4x 2 GB for $10 or 2x 4 GB modules for $10 again.) And then there was another one selling HDDs for $6 for a 320 GB mechanical. So for about $25, I got a pretty good Windows XP/7 era machine. Add $12 for something like a low-profile (was needed in my case due to the case being SFF) Radeon HD7570... and BOOM - a decently-powerful XP gaming PC.
So if you're not afraid of doing a bit of DIY in terms of adding an HDD, RAM, and doing the OS install yourself, your money can go a lot further.
In regards to the specific machines in the above ebay links... I pretty much fully agree with what chinny22 said about them.
- The 1st one (the HP thin client) will have absolutely no upgreadability. Seeing it uses DDR3, I suppose it's new enough to have a decent enough IGP for early-era Windows XP games (e.g. up to year 2002-2003, maybe.) Older Valve Source engine games is probably going to be about the cut-off point of what it can handle somewhat reasonably... and even then, who knows with those thin clients if it uses something like an Intel Atom CPU, which are not that great for gaming.
The Optiplex 3020... not bad... not bad at all! I actually saw a similar Optiplex tower the other day at the local flee market (can't remember if it was a 3020 or a 3010), but it came with 4 GB DDR3 an a 3rd gen (I think) i3 (3220?) CPU. The reason I even looked at it is because it came to my attention that these also used a standard ATX PSU (unlike my Precision T1700, which while very similar, uses a Dell proprietary pinout PSU.) Seller wanted $22 for it... which is all-in-all not a bad price for here either. But I already have enough similar Dell machines from that era, so I had to pass.
Next, the Dimension 2100.
I don't know what to say about this one, other than: run away!
Granted it's probably a socket 370 Celeron (because I don't recall P4 Celeron with such low frequencies), meaning it's a Tualatin-based Celeron. This is both good and not good. Well, the CPU part is fine. However, this means the motherboard is likely based on the Intel i810 or 815 chipset. The later would be nice, since it would give you an AGP port to use. But seeing the back of the machine already has onboard video, I'm almost certain this machine comes with an i810 chipset (and please excuse me if I'm wrong on this, as I haven't bothered to look at the Dimension 2100 specs yet.) Intel i810 = pretty poor choice for a gaming machine. For one, it means no AGP slot. So your only options for better GPUs would be PCI-based.... and those are both more expensive and poor performers usually. But that whole discussion is probably irrelevant here, since for an XP-era PC, you -will- certainly want something better than a 1.1 GHz Celeron, at least for gaming. Even early XP era games won't run that great on it. I'd say the cut-off point for this CPU would be year 2000 or maybe 2001 at absolute best. Anything newer after this will get choppy really fast.
And yeah, that listing might include a monitor... but seriously, those are like $10-20 tops even in the most boutique thrift shops. And it's a crappy 15" LCD with terrible response time. I mean, no offense to the seller of that Ebay listing... but I just don't see such system worth that much.
Lastly, the Optiplex GX780: it's another small form factor machine, and with a Pentium 4 CPU. In fewer words, it will run hot and cook itself. I used to service/refurb many such machines back in the day for reuse in a local nonprofit I volunteered at. More than 3/4 of them suffered from bad caps. So just write this one off completely, unless you want to embark on a completely new side quest here with hunting for new caps, a proper soldering iron (you -will- need it for these), and doing all the work to get that board recapped.
Now that I've opened up Ebay, let me see if I can find anything better for you. It's been a while for me.
I presume shipping will be in the US to you? And if so, mind if I ask if that would be for the East Coast, Central/South, or West Coast? I used to live on the East Coast, so I'm more fond of what shipping prices used to be there.
