You can build new- the gamers know hardware that's compatible (search Youtube and Google).
Or speed up your used gear. I choose the latter as it's cheaper and fast enough for my needs. Most brutal CPU task I do is 1080p H264 encoding on a Core3Quad 3GHz and it's fast enough for my needs. What I've mainly had to optimize is the the virtual memory system on two of my XP boxes, and 1 of my Windows 7 boxes.
If your commit charge ever goes over 1.5GB, you'll have minor to major delays from page faults. It depends on what you are doing on the box. In my case I had HUGE delays when finished editing mpeg2 HDTV video with multiple instances of VideoRedo (v2.5.7.600 lets you run multinstance). Every weekend, I may have 10 to 20 instances of VRD running, each loaded with a different 4 to 20GB mpg video file, all reading/writing at the same time, and a commit charge around 4GB. Yet I have zero paging delays in other apps. How? I put my 5GB pagefile.sys on a 5GB Superspeed RAMDisk. So other apps may be page faulting like crazy, but it doesn't matter when you have a blazing fast pagefile.sys.
A fundamental misunderstanding most folks have is about how Windows uses RAM. It's designed around a virtual memory system. Your apps (including Windows Explorer) don't run in RAM. They run in 4KB sized spaces (pages) allocated by Windows in the pagefile.sys on your harddisk. RAM is used to cache the pages for faster access. Linux and Mac are similarly designed.
Restated- Windows runs applications from the harddisk, and caches that harddisk space in 4KB sized pages in RAM. The most recently used pages are the ones that stay in RAM. When your app runs, each page is checked to see where it is. If it's in RAM, great, your app runs fast. If the page hasn't been accessed in a while, Windows says wait, I have to read it off the disk into RAM before the app can continue running.
Sounds crazy, but this was designed when RAM was much more scarce than harddisk space. Plus there are some poorly written apps that request way more RAM than they actually need, and a virtual memory system handles them just fine.
The way you FORCE Windows to always use RAM for your apps is to brute force it by having your pagefile.sys on a RAMDisk. Yes there's some minor overhead from the virtual memory system but paged out apps run almost as fast had they been in the main system RAM (copying 4KB pages of RAM to RAM is thousands of times faster than copying the same from disk to RAM).
I was the first to post about this technique in 2002 (on 2CPU.com and Storagereview forums), using Windows 2000 and Cenatek's RAMDiskNT. I got the idea to try it from the Commodore 64 GEOS graphical OS, which used the same technique- a virtual memory system paging to a RAMDisk. The test case was opening Notepad while copying like 5GB of files. 20 seconds when pagefile.sys was on a spinning disk. 1/2 second when pagefile.sys was on a RAMDisk. Keep in mind I had a Pentium III and 768MB to work with.
On XP, in 2011 I started seeing a commit charge over 1.5GB, and everything was having paging delays when ever I'd move/copy 2 or more GB of files (I do this all day with HDTV recordings). I knew immediately what the issue and solution was, but RAMDiskNT didn't load soon enough to put the pagefile.sys on it. A Google search showed the gamers discovered the trick around 2008 but the RAMDisk that worked on XP was by Superspeed:
This thread will get you started:
https://www.neowin.net/forum/topic/612086-xp-pagefile-on-a-ram-disk/page/4/
It is not a trivial mod. You'll need 8GB to try. I have to study the docs and files for days before implementing. You'll need Superspeed RAMDiskPlus v11.5.390.0 32bit. The latest version doesn't work with the mod (Superspeed claims it does). There are 1 or 2 other RAMDisks that may work with the mod. Those program names escape me at the moment. I was able to buy a license for v11.5.390.0 3 years ago. They didn't understand why I'd want to use an older version (idiot logic of newer is always better) and it took some digging on their part to produce a working license file.
I've used the mod on my main XP32 box since 2011, and not a single OS crash. I only reboot about once a month when GDI leaks force me to.
I also use it on an XP32 box I call DXP with 6 spinning RAID1 arrays and 3 SSDs (one is 2TB), for analog audio and video recording. It has a M-Audio Delta1010 rackmount soundcard and a Hauppauge HDTV/analog card (I'm only using the analog portion). I also run 2 XP VMs on the box. Commit charge is usually around 4GB but recordings are always perfect.
About your CPU- Get a Core2Quad 3GHz CPU from eBay. AFAIK, all Core2Duo boards support the Quad. Make sure to get the correct socket CPU for your system (there are several variations, study the Wiki page).
With my DC7900 boxes, I've been able to inexpensively upgrade to a 3GHz Quad by buying a non-working Core2Quad DC7900 from eBay and swapping the CPUs. The HP DC7900 comes in several case styles, but all use the same motherboard and CPU socket. The most I paid was about $40 (with shipping).
If the pagefile on a RAMDisk mod doesn't work for you, your next best option is a dedicated 500GB or larger SSD. Run only a single pagefile.sys and put that on your dedicated SSD. The faster the better (M2 SSDs). Anything smaller than 500GB, and the drive may not last long due to the limited write cycles on MLC SSD drives.
I have yet to figure out the pagefile RAMDisk mod on Win7 so I use a dedicated SSD (SATA) for the pagefile on my main file server. SnapRAID is brutal during a sync with 24 drives and even 16GB RAM isn't enough. Some days were taking longer than 24 hours to sync. I moved the pagefile to a dedicated SSD and syncs are now done in under 6 hours. Keep in mind it was on the boot SSD previously. and the only difference now was that it was on a dedicated I/O channel (yes there's tons of overhead with 4KB read/writes).
Make sure to optimize the sector alignment on all your SSDs as XP doesn't have that feature (I use Paragon's Align tool).
AHCI is ok if your system is stable with it. The Intel ICH9H chipset can have random BSOD issues with AHCI enabled. After suffering that issue for 2 years despite trying every driver Intel released, I now run all my Core2Duo and Core2Quad XP boxes in legacy IDE mode. With SSD drives, I don't see any performance difference. Windows 7 is a different story- definitely faster with AHCI enabled and I've never had stability issues on ICH9H systems (Win7 is using a different driver than XP).
