Ah ha!
Ooo good question.
In summary yep, it is indeed a fine choice. I've just realised I've gone to town on this answer.....soz
I tend to be incredibly picky about my upgrades and vfm is right at the top of the list. I know from experience that I need a new machine every 2 years or so. If it's not harddrive space it's a game I actually want (a rare comodity). I also know I, like many, cannot afford to upgrade an entire PC at once. So every year I buy specific pieces of kit to keep the entire process rolling along.
Starting with an old PC I replace the motherboard, RAM and CPU in the first year. The second year is for new graphics, harddrive(s) and other sundrie items. There are some crucial binding principles to which I adhere, one of which my recent Sempron purchase might seem to break as you'll see in a second.
The Rules
THE BIG ONE
Build the PC with a specific aim in mind and stick to it. It could be cost, certain features, or minimum performance. Whatever you do plan carefully, research thoroughly and be ruthlessly honest with yourself.
In this breakdown I'll use my own experience replacing my main rig as an example. My primary apps are Office, Dreamweaver, Fireworks, Paint Shop Pro, FTP and general communications (IRC etc). Because I also run a game mod I need to be able to run the mod tools and play games as the average user might. To top it all off I need a level of video editing to back-up my gf's editing rig.
I won't list everything I take into consideration here, it'd take hours (unless you guys really want to know ofc), but let me run through the rigs I currently own.
A History Lesson
My second ever home build PC was a from-scratch job (the previous 333MHz had seen better days). Back then DDR was just appearing and I realised it would be around for some time. I bought the first ASUS motherboard dedicated to DDR (A7M266) and the slowest CPU that supported that memory type. I reasoned that the A7M266 would have the longest possible upgrade lifespan of any motherboard then available. 1.2GHz was superfast for my needs at the time (Intels being way to expensive) and by the time the fastest processors for the mboard were a reasonable price I'd need new anyway.
This meant I could get two significant performance upgrades out of one motherboard. That saved me cash and meant I could save for things I'd always wanted. I didn't skimp on the motherboard either. At £90 it was easily the most expnsive part of that PC.
When the time to upgrade came newer CPU designs had pushed the price of the XP2200 down to £60 (the fastest PC2100 DDR chip for that mboard). That fitted nicely but suffered major heat issues and I struggled with open-sided cases and a temperamental PC for about 6 months. I decided to upgrade the fundamentals as the rest of the machine was solid.
(Moby now has the XP2200+ running open-cased under an 80mm Delta and SLK800 HS. It still won't run Seti without falling over!
)
Using the same principles as before I bought a ASUS A7V8X revised to support 333MHz DDR and the first of the XP2600+ Bartons. The CPU had to be a Barton as it suffered less heat trouble and crucially the board would support the XP3000+. My plan was to switch to the faster CPU when the price hit £50-60.
Todays Dilema
The XP3000+ still hasn't hit the right price point so why upgrade now?
Well had been pondering another upgrade and decided not to bother. Having read all I could about the latest technologies I discounted AMD's socket 754 as a waste of money. I want vfm and I was aiming at the slowest AMD socket 939. But what about DDR2 and PCI-Express? Clearly they are the technologies we'll see in PC's everywhere over the next few years!
I resolved to wait until all the technologies resolved into one format that would last me for another 2 year stint which should include the advent of 64-bit operating systems into the mainstream.
Damn Special Offers!
Ok blame this one on the PC World component centre 25% off offer recently. It was too good to ignore and I quickly considered my current situation. Some carefull purchases will upgrade my rig (mboard/CPU/RAM/PSU), substantially update my gf's editing PC (1.2GHz to the XP2600+ plus new Case/Extra RAM) AND allow me to give the XP1800 I'd repaired from work to her Dad as a Chrissy present! (he gave me a 333MHz CPU machine to setup for him, I couldn't do that too him)
Hold on! I recently bought a Radeon 9800Pro (still the best value gfx card) which will last for a year or two so why do I need PCI-Express? What about 64-bit OS'es? Not for a year at least. Hmm.
What I needed was a 754 motherboard with cheaper CPU's.
Sempron Power
"
OMG he's a tool! He went socket 754 and not the latest 939, tool tool tool"
1. Sempron 3100+ is similar in performance to the XP3000+ I originally wanted.
2. By going s754 I get a clear upgrade path to the Athlon64 3700+ when it becomes cheap (sub £60).
3. I keep my superb Radeon 9800 Pro, the second most expensive component purchase I've ever made. (I once spent £305 on a 5Gb Maxtor Harddrive
)
4. I gain the SATA, IEE1394 and DDR400 support I was lacking.
5. If AMD's pricing keeps going like it is I probably won't need to buy a new CPU for a year and mboard for 2.
To top it off I'll have got massive vfm. All the components will be used to their full extent and passed down to other machines e.g. to service the editing machine or future presents.
Advice
Sempron on Socket A
All the Sempron socket A chips are rebadged XP processors. Even without a BIOS update motherboards that supported similar speeds of XP CPU will happily run Semprons. It'll just call it the wrong name
All Semprons on Socket A are based on the Thoroughbred-B core.
Sempron/Athlon64 CPUs
Be extremely carefull when removing the heatsink. The CPU has a very large and flat surface area giving it superb vaccuum properties and possibly sticking it to the bottom of the HSF by suction along. It happened to me and made me jump when I pulled the CPU out of the socket without lifting the ZIFF socket release!
A Note on Motherboards
NEVER skimp on the quality or features. You can save money by buying a slower CPU, the RAM you NEED now and what you actually want later etc. It is the be all and end all of your machine. A motherboard failure is one of the most difficult to diagnose and painfull in cash and time to fix.
Digital out is not a digital out UNLESS you have a SoundForge motherboard. This is something I discovered only recently but apparently other digi outs are infact carry just the sterio signal for the front pair of speakers.
NCQ Harddrives
Intel 775 chipsets are currently the only ones supporting the new NCQ technology. However the Silicon Image Sil 3114 RAID chip apparently has an internal beta driver with NCQ support. This chip is used on the ASUS K8N-E Deluxe motherboard I'm using. Fingers crossed it'll support the technology.
Remember to use NCQ it needs to be enabled in BIOS and the OS must be installed afterwards or it will need reinstalling. (eww!
)
Summary
So there you have it.
Were the upgrades worth it?
Yep, all but the XP2200+ (on ebay you win some and loose almost as many). My main rig is purring along nicely. I did have an RMA nightmare with the original (MSI) motherboard which was one of the first generation 754 boards. It would have been a great board but make sure to get a second generation or first revision to ensure reliability.
I'm in the process of prepping the revised edit rig (the XP2600+ in my sig) and the XP1800+ will go to it's new home after I've had my full use of it next month!
Carefully prepared upgrades are always worth it.
I could go into even more detail and am happy to if needed. However that should do you for now. If I've missed the point of the questioning keep asking away, I'm happy to help as best I can!
I've built numerous other Athlon standard and XP based systems, Athlon64 and plenty of socket 7 madness. I'm currently trouble shooting a twin PIII 1GHz which thinks it's a twin 500MHz and our main works server which is in dire need of disc space, at least 2x143Gb SCSI Ultra320 of it
P.s.
NEVER throw any PC bits away, just reuse them sensibly