You can buy or build a PC with any configuration and upgrade piecemeal as you need to: more RAM, a bigger hard drive, an SSD, better video card, better PSU, even more case fans. But how do you decide how much to spend up front?

Smartphones are essential. Ultrabooks are great. But there's nothing to compare to the handforged desktop computer for power, flexibility, value, and upgradability. You can buy or build a PC with any configuration and upgrade piecemeal as you need to: more RAM, a bigger hard drive, an SSD, better video card, better PSU, even more case fans. But how do you decide how much to spend up front? (Aside from reading my late-2012 guide to that very subject.)

There are two basic approaches here. The first is to buy the most powerful components you can possibly afford when they're brand new, and then keep using those parts until they become unusable, at which point you repeat the process. We'll call this peak-to-peak mode, since you'll start out with a very good PC, use it until it sucks, and then get a new one that's very good.

Photo credit: Flickr user vl_33 via Creative Commons.

The other method is to do smaller upgrades more frequently. By spreading your purchases out over the lifetime of the computer, you never get the top performance of the peak-to-peak buyer, but you also are able to keep more abreast of current technology without blowing thousands of dollars every time. So you don't have the end-of-life blues of a peak-to-peak user with a $3000, five-year-old machine.

Let's walk through a thought experiment.

The Regular Upgrades Approach

It's easy enough to find historical pricing data for PC parts, and benchmarks against comparable hardware of the era, but it's harder to find apples-to-apples benchmarks of older and newer hardware. Fortunately, I have just the thing.

In the spring of 2009, Will, Norm and I were all working at Maximum PC as we prepared that year's Dream Machine builds. With the recession on our minds, we ended up doing a trio of more down-to-earth computers instead of our usual no-expenses-spared extravaganza. We specced out a $690 budget build, a $3,500 powerhouse, and a $1,420 mid-range PC, which makes a perfect sample for our purposes. We did a couple of minor upgrades to that mid-range machine in 2012--one before the Ivy Bridge and Sandy Bridge-E platforms came out, and one just after, and we benchmarked the new machine against the old each time.

Image credit: Maximum PC

The original "Budget Surplus" machine had a first-gen Core i7-920 quad-core CPU, 6GB of DDR3/1600 RAM, a Diamond Radeon HD 4870x2 GPU, and a Seagate Barracuda 1.5TB hard drive (full specs here). It cost $1,420 because we used a free release candidate of Windows 7, so add $100 for a full OS and you're at $1,520, with a PC that'll last you for several years without a problem. It's also a relatively common configuration for the time, and not dissimilar to what many of us were running at home in 2009.

If you were using this machine today you'd be severely limited by the GPU, which doesn't support DirectX 11, and no longer has driver support from AMD. You would also lack USB 3.0 and 6Gb/s SATA, and you'd be using far more power than you'd need to, but you'd have a functional computer that could still manage most games and office work.

The Upgrade

Slightly less than three years later I dug up that 2009-era rig and upgraded the GPU and RAM. For about $600 I traded the Diamond Radeon HD 4870x2 for a single-GPU Radeon HD 7950 3GB OC, and bought a 4x4GB DDR3 kit to replace the 3x2 kit that was in the board. This gave me much faster gaming performance with much less power and heat expenditure, plus access to DirectX11, which the old 4870x2 card wasn't compatible with.

A few months later, after the Ivy Bridge architecture came out, I finished my upgrades by adding a new Sandy Bridge-E CPU and motherboard, cooler, 240GB SSD, and front-panel USB 3.0. By the end, the only parts of my original 2009 rig I had were the case, power supply, hard drive, and Blu-ray drive. I spent an additional $966, for a total upgrade cost of $1,589.

This upgrade got me access to native 6Gb/s SATA and onboard USB 3.0 and gave me anywhere from 38 to 54 percent improvements in CPU-heavy programs like Vegas Pro and Lightroom.

The Perils of Futureproofing

Adding an SSD, switching to a faster GPU, or adding more RAM can all be done without upgrading your motherboard and CPU, but the tricky part comes when you finally do have to bite the bullet.

Adding an SSD, switching to a faster GPU, or adding more RAM can all be done without upgrading your motherboard and CPU, but the tricky part comes when you finally do have to bite the bullet.

I had three options when I upgraded the CPU: I could get a faster six-core CPU for the same platform, or switch to one of Intel's then-current desktop platforms. If I got a six-core CPU, I'd still be stuck on the same three-year-old platform as before, but with nowhere to go past that.

Or for the same price, I could get a new quad-core CPU and motherboard, have access to the latest technology, and still get faster performance than I had from the i7-920.

Ivy Bridge was the brand-new mainstream platform, with native USB 3.0, but lower-powered processors. Its most powerful CPU, the i7-2600K, had about the same amount of power as the cheapest Sandy Bridge-E CPU, the i7-3820.

Sandy Bridge-E was the true enthusiast successor to the X58 platform my computer was then running, with support for up to six-core processors. Ivy Bridge maxed out at four. Plus, Ivy Bridge was a dead end--if I chose an Ivy Bridge motherboard, future generations of CPUs would require a motherboard upgrade too. Intel's roadmap indicated that the next enthusiast microarchitecture, Ivy Bridge-E, would be backwards compatible with Sandy Bridge-E motherboards, so if I went with Sandy Bridge-E I had a longer upgrade path.

Image credit: Anandtech

And I would have gotten away with it, too, if it wasn't for the motherboard I chose. Even though Intel made the DX79SI motherboard and the Ivy Bridge-E CPUs that eventually launched in fall 2013, they alone out of X79 motherboard manufacturers chose not to upgrade the BIOS to allow the motherboard to accept Ivy Bridge-E CPUs.

So the bad news is that that platform is once again at a dead end unless I replace the motherboard and CPU. The good news is that that CPU is still plenty fast, and should be fast enough for any game you're likely to play in the next three or four years, as long as you have the GPU for it.

What I'd Upgrade Today

If this was my home computer, I'd be pretty much set. The only thing I'd add would be a larger SSD, like a 500GB Samsung 840 EVO, for games, and a 3TB drive for storage. That'll run me about $400 total. The GPU and CPU are still more than enough unless you're getting into multi-panel or high-res gaming, in which case I'd spend $500 on a GeForce GTX 780.

This actually isn't too far off from my personal computer, which I last upgraded in 2012, with an i5-2500K, 16GB DDR3/1600, Nvidia GeForce GTX 680, two 256GB SSDs, and a 3TB hard drive. The only reason I'd have to upgrade this nearly two-year-old PC would be to move from micro-ATX to mini-ITX, and that's not a good enough reason for me. My current GPU still lets me game at 2560x1440 on high settings, so it's good enough.

Spending More Up Front

We've seen what happens when you spend $1000-1500 every few years to upgrade your PC. So what happens if you buy a $3000 PC, then don't touch it for 5 years? Let's take the $3500 "Stimulus Package" PC, from that same 2009 Dream Machine feature, and see how it holds up.

The Stimulus Package consisted of a six-core Intel Core i7-975 Extreme Edition CPU, two GeForce GTX 285s in SLI, 6GB DDR3, a 256GB SSD (in 2009!), 1.5TB hard drive, and a 910W power supply.

Image credit: Maximum PC

When we built both machines, the Stimulus Package was $2,000 more than the Budget Surplus. It was percent faster in Unreal Tournament, 75 percent faster in Crysis, 10 percent faster in MainConcept, and about 15 percent faster in Photoshop and Premiere Pro. Put that way, it hardly seems worth it, but surely it paid off in the long run, right?

Well. Maybe. Except in heavily multithreaded benchmarks, that i7-975 is basically a wash with the i7-3820 in the upgraded Budget Surplus. Those dual GTX 285 SLI boards are hot, loud, and don't support DirectX 11, and aren't any faster than the cooler, quieter, less power-hungry Radeon HD 7950. The Stimulus Package also has a much slower SSD, and no support for USB 3.0 or SATA 6Gb/s.

With the Stimulus Package, we spent $3500 in 2009 and are left with a machine that is outmatched by a $1500 machine today. On the Budget Surplus machine, on the other hand, we spent $3000 between 2009 and 2012 and have a faster, more modern machine to show for it in 2014, plus enough money left over to upgrade to a faster GPU this year. It makes more sense to spend smaller amounts of money more frequently.

Of course, for $1500 today, you could build a micro-ATX machine with a Haswell quad-core CPU, a 500GB SSD, 3TB hard drive, GeForce GTX 770, and 16GB of RAM that's faster, quieter, and more energy-efficient than either the upgraded Budget Surplus machine and the original Stimulus Package. But that's progress for you.

When to Upgrade: Follow the Cycles

You should prioritize GPU and SSD when it comes to upgrading your existing PC, unless your CPU and motherboard are truly ancient.

CPU performance has only improved about 10 or 15 percent clock-for-clock for the past few generations. The real reason to upgrade to a new CPU and motherboard is for the ecosystem: 2011's Sandy Bridge finally brought native 6Gb/s SATA ports to the Intel platform (if only two), while 2012's Ivy Bridge was when Intel added native USB 3.0. Both of those can be had via add-on PCIe cards, which is what we did in our first upgrade to the Budget Surplus machine, but performance on the native chipsets is better.

As Loyd Case has pointed out as long ago as 2011 and as recently as last September, you should prioritize GPU and SSD when it comes to upgrading your existing PC, unless your CPU and motherboard are truly ancient. If you have less than 8GB of RAM, you should get up to at least 8GB. If you don't have an SSD yet, aim for a high-capacity midrange drive, like the 500GB Samsung 840 Evo.

A five-year-old quad-core CPU is still just fine for gaming and home office work, so the only reason to upgrade your motherboard and CPU is if the old ones stop working, or you want to take advantage of new technologies like SATA 6Gb/s, USB 3.0, or PCIe 3.0. Or if you just want to move to a smaller, more energy-efficient form factor. Can't blame you there.

Photo credit: Flickr user putu via Creative Commons.

What about You?

Desktop gamers, how old is your current PC? Are you happy with it? What's your next upgrade? Are you starting from scratch, or doing an incremental update?