Is there any minus points in using xp sp3 oct 2013 patched

I'm saying that the OP might be stating that each version that he/she installs is a clean install. He/she lists XP, W7 and W8 as Operating Systems recently worked with. It is a stretch, but I was attempting to reconcile the thread title with the claim of not updating.

I'm not saying that anyone could or should do an "in place upgrade" from W7 to XP.

As for why anyone would want to go back to XP...
...maybe it is so that they can get their work done.

I still have work related stuff that will not run on W7. Some of it I wrote myself and I've not found a way to rewrite the code... so an XP box or two is still around. Just last week I had to give up on an W7 install and revert to XP.

I don't think there is nothing inherently bad with your decision, XP is a quite capable OS and will continue to be fully functional for much more time.

Looking at your specs, they seem a bit humble for Win7 to run properly under load, while XP will probably be OK, most programs will also run exactly the same, as pretty much everything out there is XP-compatible these days, unless otherwise noted on each site.

The things I would probably miss are UAC and a relatively good firewall that comes with Win7, both security related, and a somewhat better updating interface and stability. Some very particular MS programs are also artificially limited to run on Vista+ system (notably Office 2010), and I'm sure there may be some few others out there with similar restrictions.

The only thing that you should watch out for are hardware drivers, as these need to be specifically compatible with XP to work properly.