If you have a little time to look around and wait for a deal, I found/bought at Cowboom, Dell XPS 8700 , i5-3.2GHz, 12GB ram and 1TB HD for $349 (used), but very good condition. I later added 500GB EVo SSD. I am very happy with performance.
Although there are truly several things to consider, as you can see with all the varied responses here, the single biggest performance boost you can get from ANY computer is to change from HDD to SSD for the OS and applications. User files can be kept on the larger, though much slower, HDD. It has been true for over a decade at least, that the HDD is the single bottleneck of any modern computer. It is the slowest part (except the CD drive, but it’s not used for normal operation).
How about a low end Mac Mini?
+1.
Join SlickDeals and add a Deals Alert for DELL. Then sit back and wait for the best deal possible.
See if this PC will run a Q6600 processor— you can usually root around online or look on the motherboard for board number—I found this CPU for $20 ebay—it will smoke that 745— then add a SSD drive—they sometimes come with cloning software— do a clean install (best way to go)using your key code windows 7 install files are easy to come by—using a second drive is really essential especially with SSD main drive—you put all your storage on a standard drive—-
someone had given me an old Q6600, i ended up tossing it (or did i give it away, i don’t remember)
Check out www.techbargains.com for daily crazy deals or www.cowboom.com has daily refurb items fro super cheap. Newegg has a Crucial 500gb SSD for $134.99 right now.
The days are long gone when the speed of a processor can be judged just by knowing the model # There are now thousands of different iterations of processors/ The only way to know how each one will benchmark is to refer to this exhaustive list.
Considering a certain system? Check the cpu from that list and know what you are getting for speed. For example, the Q6600 quad core that chops728 scored for $20 on ebay benchmarks at 2900. That chip is unavailable on Newegg, but was $176
Your original core duo probably is less than 1000.
The system I suggested above with a core i5 2400 benches at 5836.
It is time to get your priorities straight here. Your say your budget is $400. Spend $199 for the system, another $60 for a 240G SSD, $15 for a USB 3.0 card and you are all set. You will have a plug and play system all set up with a legitimate copy of Windows 7 that Microsoft will let you upgrade to 10 if you wish, and MOST IMPORTANTLY,
You will have lots of bucks leftover to spend on flashlights. 
LOL!
I like this website because you can pick two CPUs and it will compare them for you
http://www.cpu-world.com/index.html
You can add a SATA III SSD to your system as SATA III is backwards compatible. Should be the white/black connector next to the heat sink/Dell logo http://www.stuartconnections.com/9068-thickbox/Dell-Optiplex-745-MiniTower-System-Motherboard-Socket-775-HR330.jpg you’ll need to buy a SATA cable too.
Bort, I never came across your site.
What I like about the one I mentioned is that it lists all variations of each cpu.
For instance, there are over 200 types of Intel core i5’s and they benchmark between about 1200 and 8000.
That is a huge difference, it is of utmost importance to know exactly which i5 you are getting and what speed it will bench at. That list will tell you.
This is also true for every other cpu, whether AMD or Intel
Remember when all you needed to know was 286 or 386 and the clock speed?
I forget how i came across it. Ironically the new i5 is only 10-20% better then my i4670, not even worth it IMO
Yup 386 DX 20, then Pentium 75
dc,
That is a great list. I have been using a similar one off wiki
But the one you linked is much better.
You were also darn close about my old processor. Its a Pentium D 3.4GHz. Looks like it benches at 745.
I wouldn’t upgrade a 745. We just got rid of all of our 745s, 755s, and 960s. We’re currently using 7020s. Yeah, Dell’s Optiplex numbering system is f’d.
Contrary to the trope, pc sales haven’t declined strictly because of cell phones and portables imo… they’ve declined because no one who’s bought a pc since 2010 really has a need to upgrade. Basically any intel based processor / pc built since 2010 is pretty capable in my eyes, meaning any of the Core iX cpu’s. 8GB ram is the minimum for good performance; 16 if you do video editing / CAD work. Adding a low end graphics card will get rid of any full screen youtube / flash stuttering problems if they exist. If you buy a pc and it only has a standard HDD in it, I would suggest adding in an SSD (minimum 128 GB) such as a Samsung 850 evo, reinstalling windows or linux onto it and using it as your primary boot drive. This will do the absolute most for the “user experience” and it’s only a $65 upgrade or so. Use the original HDD for bulk storage and another place for data backups.
I’ve seen some crazy deals on ebay. Decent used business pc’s being sold from bulk lots for sub $200. Be sure and see if it includes the OS key as part of the deal. Legit W7 is only about $45 these days though. W10 (Bleh!) is $100.
Yes if a fresh windows install for free does not do the trick, I am with Hoop here
And that 240GB SSD mentioned above is decent size and price, ergo good choice!
Yea that price is a steal for that 240gb ssd. I’ve had enough trouble with SSD’s over the years that these days I only buy from Samsung who makes both their own controller and memory chips. A couple years back they were the only manufacturer doing so, if they aren’t still, and they have a solid track record. I also only buy Seasonic power supplies, but that’s about the extent of my brand loyalties. Well, I’ve been satisfied with Gskill memory and MSI mo-boards over the years too but would also consider other brands for any new build. Oh, Hitachi / HGST hard drives have the lowest failure rate and I use them in my RAID arrays.
Seasonic was my to go brand as well for PSUs
There are other brands who rebranded them and sold them a little cheaper but it is too long ago do j don’t know which knrs are those nowadays.
Ok I think I am getting close to knowing what to do. I will probly get a decent PC to start and add the SDD and if needed some ram.
I was thinking about maybe this.
http://www.ebay.com/itm/Dell-3010-Desktop-i5-3470-3-2GHz-4GB-RAM-1TB-HDD-Win-7-64-Bit-DVDRW-HT3DPV1-/222029413804?hash=item33b1fbfdac:g:xx8AAOSwg3FUh1~e#viTabs_0
First plus is its a Dell ( although I would still consider and HP).
Newer version than my 745
Fairly new i5 3470 processor
Thoughts???