If it's been a while since your last PC upgrade, chances are good that you stand to benefit from a refresh to your hardware. While in theory anything with a Core 2 Duo / Athlon X2 (the later variants at least) or newer is still "fast enough", gains in efficiency not to mention system responsiveness are definitely worth pursuing. And if you're having any sort of stability problems on an older PC, trying to fix things can often end up costing just as much time and money as simply starting anew.
While picking out parts for a new PC is relatively simple on one level, the trick is in choosing parts that provide a good combination of price, performance, reliability/stability, and features. Despite advances in technology, the reality remains that going out and buying the cheapest motherboard often means you get exactly what you paid for: a cheap motherboard. That might mean things like compatibility issues with certain devices (e.g. DIMMs or PCIe cards), instability, and/or other issues. Troubleshooting such problems is no fun, so saving $20 at the cost of hours of lost productivity isn't something I'd recommend.
For other parts, however, the choices are pretty straightforward. CPUs/APUs rarely cause instability or other problems on their own, so the only real factor in selecting a processor is how much performance you want and how much you're willing to spend. I'll be listing several potential processor choices below. Storage and memory are for the most part compatible with any good motherboard and are largely interchangeable -- again, the decision mostly boils down to performance and capacity versus price.
Finally, there's the question of whether you should go with an Intel platform or an AMD platform -- and within each company, which platform is best? This topic often devolves into emotional arguments about monopolies and what is or isn't fair if you're not careful, but I'll go ahead and choose what I feel is the best current platform for each company below.
Recommended Intel Budget PC
Starting with Intel, this is the build I recommend for most users. The reasons are pretty simple: Intel offers better single-threaded performance, which still matters for many everyday tasks, Intel's platforms/chipsets tend to be more reliable than the competition, and when you get down to the final cost the difference between AMD and Intel platforms often isn't that much. Also, if you're buying a new PC it's generally better to have a newer platform in terms of longevity, so I'll be sticking with Intel's latest LGA1150 parts rather than the older LGA1155 options. Let's get to it....
Intel Budget PC Components
Part
Description
Price
CPU
Core i3-4160 (2x3.6GHz + HTT, 3MB L3, 54W)
$118
Motherboard
MSI B85M-G43
$75
Memory
Kingston HyperX FURY 2x4GB DDR3-1866
$63
Storage
Crucial 250GB BX100 SSD
$99
Case
NZXT Source 210
$40
Power Supply
Corsair CX430
$40
Total Price
$435
Starting with the processor choice, with Intel there are basically four options: Celeron, Pentium, Core i3, and Core i5. I've elected the middle choice of the Core i3-4160, as it provides a good clock speed as well as Hyper-Threading while targeting a reasonable price. The Core i5-4460 is a quad-core part but without Hyper-Threading for about $70 more; alternatively, the Celeron G1820 or Pentium G3220 will save you $70-$80 but you lose some clock speed, L3 cache, Hyper-Threading, and a few other features. As an all-around choice I like the Core i3 because it's fast enough for all but the most demanding use cases and it isn't artificially limited in other ways (e.g. disabling Clear Video or AVX/AES-NI). For lighter use cases, however, the Pentium and Celeron chips are still sufficient, and the unlocked Pentium G3258 offers a healthy amount of overclocking.
For the motherboard, my requirements are pretty simple: I wanted something that supported four DIMMs and I wanted a DisplayPort video output. That eliminated a large number of options, and of those that remained the MSI B85M-G43 is a good budget choice. Note that if you want to dabble with overclocking (e.g. on the Pentium G3258), you'll need to spend more on the motherboard to get an appropriate chipset. Also note that in many cases, even with overclocking the Core i3-4160 is going to be as fast as or faster than the G3258.
Memory isn't much of a concern for the most part; get anything and as long as it works in your motherboard the difference between the fastest/most expensive DDR3 memory and the mainstream DDR3-1866 I selected is going to be 1-2% at most. 8GB is a good starting point for a budget system and it should keep you running happily for a while.
Probably the most difficult item to convince people to upgrade is the storage, where I've selected Crucial's BX100 250GB SSD. Priced at $99, some users will immediately look at a 2TB hard drive and think, "For less money I can get eight times as much storage!" That's true, but the impact of using an SSD can be equally dramatic when it comes to simple things like booting Windows, loading a bunch of browser tabs, installing applications, etc. In fact, if you have any PC built within the past five years, I'd suggest seriously looking at upgrading to a $100 SSD like the BX100 first, maybe adding RAM if you have less than 8GB, and then decide if your PC is still too slow.
Wrapping up the build, we have a popular ATX case from NZXT and an energy efficient 80 Plus Bronze PSU from Corsair. You could go with a micro-ATX case as well, or a smaller wattage PSU, though neither will really save money. All told, the final price is well under $500, though you still need to account for the price of the OS -- Windows 8.1 will typically cost around $90. You might also be wondering about the lack of an optical drive (DVDRW); those are easy enough to add if you want one, but I've found installing Windows from a USB stick is just as easy and I rarely use CDs/DVDs these days.
I've put together the following list of alternatives for those looking to get either a fast/more expensive system or those who are willing to sacrifice some performance if it will keep the cost down. Note that while you can use any ATX or Micro-ATX motherboard in an ATX case like the NZXT Source 210, if you buy a Micro-ATX case you'll need to pick a Micro-ATX or smaller motherboard.
Intel Alternative Components
Part
Description
Price
CPU
Celeron G1820 (2x2.7GHz, 2MB L3, 54W)
$43
Pentium G3220 (2x3.0GHz, 3MB L3, 54W)
$57
Pentium G3258 (2x3.2GHz, 3MB L3, 54W, Unlocked)
$70
Core i5-4460 (4x3.2-3.4GHz, 6MB L3, 84W)
$190
Motherboard
MSI H97M-G43
$90
ASRock H97M Anniversary
$71
Alternative AMD Budget PC
The AMD side of the story is somewhat more complex to dissect. First, there are still several platforms from AMD that are all somewhat viable. I'm going to go ahead and eliminate the AM3+ and FM2 from consideration, however, as both are now old enough that if you didn't buy them already there's not much sense in doing so now.
A funny side story here is that AMD did a presentation earlier this year showing how they offered better value compared to Intel by showing how DX12 and Mantle made the CPU performance advantage of Intel largely meaningless. The problem is that they were still showing their old FX platform as the value option, and while the platform is certainly fast enough it also tends to draw more power, thus making more heat and noise and requiring better cooling. The net result is a wash, at best.
Long story short, I told AMD that the FX platform was "dead to me" -- that there was no reason to recommend it at this point as nothing really noteworthy has happened in a couple years. If CPU performance doesn't matter, a modern AMD APU is a better choice than an old FX-6300 CPU, but for CPU performance to truly not matter we need all games to use DX12 or OpenGL Vulkan (or Mantle I suppose). Right now, DX12 and Vulkan games don't exist and they won't exist for another year or more in any substantial way; heck, we still have lots of DX9-only games that come out.
AMD's story only really works if you care about having a faster GPU on your processor. If you're going to use a discrete GPU, just go with Intel and be done with it. And if you think the GPUs in AMD's APUs are sufficient for gaming, you're probably willing to accept 30 FPS at low to medium settings with a lower resolution. The real problem is that if you want AMD's fastest APU graphics solution with 512 cores, you'll also need to pony up for an expensive A10 processor, at which point you would be better off just buying a processor that doesn't have graphics and getting an even faster dedicated GPU. Anyway, if you refuse to buy an Intel system, here's a comparable AMD build:
AMD Budget PC Components
Part
Description
Price
APU
A8-7600 (4x3.1-3.8GHz, 4MB L2, 65W)
$96
Motherboard
Gigabyte GA-F2A78M-D3H
$60
Memory
Kingston HyperX Fury 2x4GB DDR3-1866
$63
Storage
Crucial 250GB BX100 SSD
$99
Case
NZXT Source 210
$40
Power Supply
Corsair CX430
$40
Total Price
$398
At first blush, it looks like going AMD will save you about $35 (give or take) compared to the Intel system. That's true in some ways, but we have to dig a bit deeper to show where things aren't quite comparable. For one, the Intel motherboard actually has a DisplayPort output -- ironic that AMD with the better processor graphics only has DisplayPort on rather expensive motherboards.
Another important point is that while clock speeds are similar, Intel's Haswell architecture is in general about 50% faster than a similarly clocked AMD core (e.g. the i3-4160 scores 145 points in the single-threaded Cinebench R15 test compared to 87 on the A8-7600). Even in multi-threaded testing, there are many cases where Core i3 will handily beat A8-7600 (365 in Cinebench R15 vs. 292). The reality is that the only time the A8-7600 can match or exceed the performance of the i3-4160 is in benchmarks/applications that leverage the integrated graphics -- which mostly means games and image/video processing.
Choosing a motherboard for AMD is also a bit maddening. There's no "ideal" board with a reasonable price, so the Gigabyte board I selected misses out on DisplayPort as noted above. If you want DisplayPort, the least expensive board with reasonable customer satisfaction that I can find is the ASRock FM2A88X Extreme6+, which would wipe out the pricing advantage of the AMD platform. There are less expensive boards as well (just as on the Intel platform), but none that I really trust. Overall, the features on the GA-F2A78M-D3H are pretty good, with four DIMM slots, two x16 PCIe slots (one PCIe 3.0 and one x4 PCIe 2.0), and the usual collection of other ports.
The other side of the story is that AMD's processor graphics really are superior to Intel's graphics. At best, AMD is still around 50% faster than the HD 4400 in the i3-4160; at worst, the A8-7600 can be more than twice as fast as the HD 4400. There are plenty of recent games that still don't run at acceptable performance on Intel's HD Graphics 4600 with an i7-4770K for example -- Assassin's Creed: Unity, Civilization: Beyond Earth, Company of Heroes 2, Dragon Age: Inquisition, Dying Light, Far Cry 4, Lichdom: Battlemage, Lords of the Fallen, Metro: Last Light, and Middle-Earth: Shadow of Mordor for example all fail to average more than 30 FPS even at 1366x768 and low settings (and several of those titles fail to break even 20 FPS average). But any moderate dedicate GPU will solve that deficiency if you want to play games.
The remaining core components are all the same as in the Intel build, but here it's worth mentioning that AMD's Kaveri APUs and Bolton chipsets officially support DDR3-2133 memory. That can further improve the integrated graphics performance, though it will typically increase the total system cost by $30 as well -- and that $30 would often be better spent on a faster dedicated GPU if you're looking at graphics performance. That gives us a few alternatives for the AMD platform worth quickly discussing:
AMD Alternative Components
Part
Description
Price
APU
Athlon X4 860K (4x3.7-4.0GHz, 4MB L2, 95W)
$74
A10-7800 (4x3.5-3.9GHz, 4MB L2, 65W)
$144
Motherboard
ASUS A88XM-E
$55
ASRock FM2A88X Extreme6+
$95
Memory
Kingston HyperX Savage 2x4GB DDR3-2133
$95
I mentioned that you need the A10-7800 to get all of the GPU resources in Kaveri enabled, but that bumps the price all the way to $144 and you'd probably want to go with DDR3-2133 at that point. Interestingly, you can instead pick up the GPU-less Athlon X4 860K with DDR3-1866 memory and put the $100 towards a discrete GPU. I've also listed a couple more motherboard options, basically a higher-end and lower-end option.
As a budget gaming system, I think AMD is still viable, but it's becoming an increasingly tenuous proposition. Overclocking doesn't help things either, as it takes an APU that already uses a bit more power than its competition and then redlines it. It's like comparing the R9 290/290X against NVIDIA's offerings: yes, AMD can offer competitive performance, but when it comes to efficiency they're simply outclassed.
We need to see some pretty major changes for things to improve, and sadly I'm not sure that's going to happen any time soon. In fact, Kaveri was actually more of a step sideways for AMD CPU performance -- Richland APUs were typically clocked higher but they aren't as efficient. Will AMD's next CPU architecture, Carrizo (Excavator) help? Given that AMD is talking more about mobile products and non-socketed BGA desktops from OEMs, I wouldn't expect much to change. We'll have to wait for K12/Zen from AMD to have any real hope of seeing an improved CPU core.
Other Alternatives
For some alternative options to the above, I've put together the following list of components. These can be used with either the AMD or Intel builds; just be sure to match up the motherboard size with the case size, and if you want the option to add a higher performance graphics card in the future you should look at adding a power supply with at least two 6+2-pin PCIe power connectors. I strongly recommend against going with a pure HDD storage solution, but if you want lots of capacity there is the possibility of adding a 2TB drive as the secondary drive for $70.
Other Alternative Components
Part
Description
Price
Storage
Crucial 256GB MX100 SSD
$110
Crucial 500GB BX100 SSD
$185
2TB 7200RPM Hard Drive
$70
Optical Drive
Samsung SATA DVDRW
$17
Case
GIGABYTE GZ-X7
$55
HEC 6K28BB8F
$41
Power Supply
SeaSonic SS-300ET
$40
Rosewill Valens-500
$60
Graphics Card
Radeon R7 260X
$117
GeForce GTX 750 Ti
$140
And if you wanted to build a gaming system using the above, it's pretty easy to do so. Take the Intel build (because, no matter what anyone else tries to tell you, Core i3-4160 will beat just about every AMD APU for gaming when paired with a discrete GPU) and then add as much GPU as you feel you need. From the Graphics Card Guide posted last week, you could build quite a potent gaming rig for as little as $650 (i.e. with the GTX 960 or R9 285). You could also keep pricing closer to $550-$600 if you're willing to go with the R7 260X or GTX 750 Ti listed above.
What that means in a broader sense is that if you're already looking at buying a new PC, you can get far better than PlayStation 4/Xbox One performance without breaking the bank. Not only that, but you'll be able to keep playing any of you PC games for years to come, on future newer/faster/better PCs.