For the bigger builds, we have two:

• Haswell Cube. This is based on the mini-ITX and is the fastest setup if you want a high performance double-width graphics card.
• Haswell Mini-Tower. This is the smallest box that can handle an overclocked dual SLI graphics card setup. This means we are moving up to the micro-ATX level as these have two PCI Express slots

Haswell Cube

This uses the same build pieces as the Haswell Flat, but the main thing to figure out is the nicest cube case. You want something small but able to take ideally a pair of full length video cards, an 450 watt power supply and a big 120mm heat sink fan. So here are the build recommendations based first of all on the enclosure. See PC Part Picker for the full build and here is the explanation:

Enclosure

In this more traditional size, the key question is how big is big enough. Anandtech does great reviews of cases mainly because they include the HSF heights and what will fit. These case range from 10 liters up to 12 liters (while the Haswell Mini-Towers are more like 25 liters and the Haswell Flat is 6 liters).
These cases require a short slot GPU but are much smaller and given there are quite a few mini-ITX GPUs now, they are probably the top choice. Silentpcreview.com has a good overview of mini-ITX cases (and even recommends the SG-10 for micro-ATX see below)
### Less than 14 liters
There isn't much choice here, but if you want a 14 liter system, you have two:
Silverstone SG05-Lite. This has a 600 or 450 watt SFX power supply and needs a short dual slot graphics card and about $130, so a good compromise with support for 147mm Cpu coolers, 2x2.5 drives, 12.2 inches or 309mm cards (but then you need a 140mm short PSU like an SFX unit like the SX600-G). Looking at the power requirements, a single card should take about 450 watts, so that is good even with a 20% capacitor aging. It is a relatively small 222x351x190mm (14 liters). The cooler height limit is 82mm and the GPU card length is 10 inches (254mm) Ncase M1 V3. This is crowdsourced and relatively expensive at$180+55 shipping but it uses SFX and allows a full length slot and full height cooler and you can even fit a water cooler into it. which is pretty amazing. V3 orders close next week so it is expensive and limited edition. Only 12 liters though and allows a full slot which is pretty amazing. It's the dream even if super expensive at $220 with limited production runs. 15 liters and above If you essentially increase size by a little then you can get to bigger graphics cards as there aren't many short ones and the ASUS Strix is so quiet. • Silverstone SG-08 Lite. 15 liters It is slightly longer than the SG05 but very, very quiet. It is expensive at$150 at Newegg without a power supply. It’s capable of handling overclocking too. The real advantage here is that it support graphics cards up to 12.2 inches long (309mm). It's a great case for that. And it allows thin tall coolers that are up to 147mm high. This is a big deal as for mini-ITX, there is not much area dimension so you want a tall cooler. The tradeoff if that for GPU cards longer than 7.25" you need a non-modular PSU shorter than 140mm (160mm is standard ATX).
• Fractal Design Node 304. 19.5 liters. One of the larger cases but it can take a full ATX power supply and 4 hard drives plus a 12" standard GTX card.

• Thermaltake Core V1. It fits a 255mm long graphics card, ATX power supply. As Anandtech says, the Thermaltake Core v1 is another example of a mini-ITX  that can handle a short 260 GPU, 140mm CPU cooler and a full sized 200mm ATX power supply. It is relatively small at 10.9x10.2x12.4 or 22 liters. And is just $50. • Corsair Obsidian 250D.$85 and top rated at Newegg. It's bigger, but it can handle a full sized slot at 13.8x10.9x11.4 so is 30 liters. But it can hold 2x3.5, 2x2.5, ATX, 290mm GPU card.

• Bitfenix Prodigy. Probably more than you want for an ultra small build, this one is 31 liters and lots of storage potential.

• Rosewill Legacy W1-S. Also large at 30 liters it is shaped like the nCase M1.

• And just shipping are some more:

• Xigmatek Eris. This one was just announced but at $60 has about everything you need including full length, double-slot GPU card support, ATX power supply, 140mm tall CPU coolers. They do this by having only one 5.25 slot. But with M.2 on the motherboard you don’t need that much additional storage space anymore as many of the systems have. • MSI Nightblade Z97. This include an MSI motherboard and a 600 watt supply and can take a full length card 290mm long and 35mm wide. And they have them at Fry's. Not a bad choice given you just need to add a CPU, GPU and some memory. It's got "gamer" styling though, so you want to think about that. • Cooler With the SG-05B, you need a cooler that is shorter than 83mm. The Big Scythe Shuriken B is 58mm high and does fit. If you get a large system, then you just need to make sure it isn't too big and wide so ideally you want a case that allows a tall 140mm high cooler so it interferes less, but that is usually a bigger case. Power Supply Ironic how enclosure and power supply are so important right now in these tight spaces. They are almost the first things to talk about. ATX looks really big in these small cases, so there is Flex (150 watts) and SFX. SilverStone SFX SX600-G breaks ground as a 600 watt supply. It's expensive at$140 at Newegg so if you can handle it the $80 450 watt unit is the place to go. The system draws 300 watts without overclocking. Adding overclock probably adds at most 40 watts for CPU (88 to 120 watts) plus 20% capacitor aging, so a 600 watt supply is overkill, but 450 watts is probably at the limit assuming overclocking isn’t too heavy although the eVGA card recommends 500 watt minimum. • FSP450-60GHS. This is identical to the nice SX45SF-G if you don't have a monster graphics card. And is much cheaper at$65 on Newegg. Using the Extreme Power calculator this is just about enough assuming 10% capacitor aging, so pretty tight, the 600 watt is more conservative.
• SeaSonic X-520 Fanless. This is ATX, so good if you decide on a larger case. Unfortunately too small for our build, it is a pretty incredible device. No fan at all and 500 watts.

• Motherboard

Silentpcreview.com does have a good overview of motherboards that are Z97 (e.g. that can be overclocked). Most of the difference focus reliability, power control (so you can overclock better) and on features. The key features are having mini PCIe for network and M.2. Of the two, I'd rather miss the m.2 as you can get a wifi dongle pretty easily on USB 3.0. You can really go crazy with a low of $120 up to$300 (!) if you want. Anandtech also does a review of some motheboards:

• ASUS Maximus VII Impact. While expensive, this has x4 PCIe on M.2, mini PCIe for wireless. it does this with a mini PCIe daughterboard that holds both wifi and m.2. The bigger issue is that like most mini-ITX boards, the ram slots are right next to the cpu, so you need a relatively narrow cooler. Expensive at $220, but the m.2 x4 is pretty cool. This is a bleeding edge board and in actual gaming practice, the performance difference is small (to be expected as the disk isn't the limiting factor). • ASUS Z97I-Plus. It has x2 PCI M.2 and built in wifi, so it's a good choice if you don't need the storage speed. Plus it is much cheaper at$140 rather than $220. You can use the very good Plextor M6e and get better than SATA performance (30% better, vs 3x on the ASUS Maximus). We've been using the ASUS H97I-Plus in our Haswell quiet flat systems, so this is a good one to look for a quiet build. • AsrRock Z97e-ac. This has 802.11ac, but the m.2 slot is only 40mm so won't fit the really fast m.2 cards. • MSI Z97I AC. The right specs, but poor layout for getting this thing squeezed into a tight chassis. • Gigabyte Z97N WIFI. Good placement and has wifi mini PCIe slot and no m.2 so that's a problem. • Processor The processor for this build should be one that is either fast or where you allow overclocking if that is OK. One interesting point is that even silentpcreview thinks that the 65 watt S parts aren't really that much different in performance or in cooling than their 85watt brothers, so if you don't overclock, you just buy on price (that is$/incremental GHz).

• 4590K. The overclocked Core i5 at $240 is a great deal. Usually gets to 4GHz plus from it's base 3.5GHz • 4790K. You only need this Core i7 for things that need lots of memory and storage like Photoshop. Gaming doesn't use it much however, but it's amazing for other applications. • SSD With the new motherboards support m.2, it sure is convenient to get a m.2 card and save even more space particularly on a mITX build. But it is complicate which one to get But if you have an m.2, then you can get the Samsung 941 which is PCI Express x4 and so is faster than SATA Evo 850 Pro comparison. The 941 is very fast at 5% and much more compact. The 850 Evo Pro is much cheaper ($300 for 512GB vs $500 for 941). The m.2 runs very hot and needs a cooler and the 941 is an x4 PCI Express but most motherboards are just x2 so you need to check. So comparing it with a traditional x2 PCI Express and m.2. If the drive uses an SATA to m.2 it will be as fast as SATA, but will be more compact. One important thing is that with today’s controllers, these drives run very hot at over 110 C. But most motherboards can boot. The second sort uses PCI Express x2 directly and run 30% faster. For the 941 at x4 if you have an adapter it can be twice as fast but you should use it on PCI Express as kind of a poor man’s NVMe system. The combination is pretty dynamite, but things are getting better, the upcoming according to Anandtech http://www.anandtech.com/show/8773/asus-maximus-vii-impact-review-premium-gaming-z97-in-miniitx comments: The Samsung SM951 is expected to be NVMe compatible, and will be capable of up to 1,600/1,000 MB/s sequential reads/writes and 130K/100K IOPS 4K random reads/writes – slightly faster than the XP941 rated for 1,400 MB/s sequential reads. The drive is also NVMe low power (L1.2) certified and is rated to draw <10mW power at idle (probably DevSleep mode). Available in capacities up to 1TB Storage A good question. For really fast machines, you want a boot drive and then a storage drive. A motherboard that has an M.2 interface is really convenient and the drive takes zero space. Looking at thessdreview.com gives you a sense of good drives as does the Tom's Hardware. • M.2 4x PCI Express with right motherboard. The Samsung X941 though does 1GB read and X941 native PCIe M.2 but this requires x4 lanes (20Gbps or 3x that of SATA) which isn't common on a motherboard, so you really want to use this with a PCI Express adapter to get 4 lanes. However on our builds, we don't have an extra 4-lane slot on a micro-ATX board. So this is really for large builds like the Haswell Workstation we've talked about before. If you get it being 3x faster than SATA is pretty nice! It isn't a bad stutter step before the true NVMe boards like the Intel P3500 come out. Cost-wise it is expensive at about$500 for a 512GB drive. This is the same drive by the way that is used on the new Apple MacBooks.
• M.2 PCI Express x2 SSD. These are in the sweet spot of pricing right now. Check that the motherboard is a x2 M.2 and you are golden. Then you need a true PCI Express native x2 like the Plextor M6e and you should see 30% more performance (6Gbps on SATA vs 10Gbps on PCI Express x2). These things are expensive at about $1/GB (250 for 256GB), but nice to have when booting. • SATA SSD. The Samsung Evo 850 Pro takes the cake. If you look at pricing the 256, 512 and 1TB drives are all along the same price line. Maybe there with the 512GB having a 2% sweet spot advantage. It's about 20-30% faster than the very good Crucial M500 as an example and maxes out the 6Gbps on the SATA drive. About$330 for a 512GB drive.

• For other applications:

• M.2 SATA based SSD for the budget. We've been using the Corsair M550 and they seem fine. The transcend looks pretty good too. These are typically 500MB read and 120MB write so good mainly for boot drives.

One note about M.2 assembly. These are strange but very compact systems. The main thing is to figure out how to screw them in. There is a magic screw which you take apart revealing a spacer that you screw in and then another one. Also these are on the reverse of motherboards. Finally, you have to know if they will take 2260 (short) or 2280 (long) and what they are keyed M or B. Got it yet?

GPU

Right now pricing-wise, the GTX970 is probably right at the sweet spot. The GTX980 is about $600 and the 970 is about$400 with 90% of the performance. The challenge is to find something that will fit in a small case (unless you buy the M1). Again HardForum comes to the rescue as we look for short card GTX970s albeit dual slot, so you still need room in there. You need a relatively short card at less than 254mm to fit and you want one that is quiet.

• EVGA GeForce GTX 970 Superoverclocked. Fast and just 9.5 inches, but it is loud.

Galax GTX970 Short at 193mm.

• ASUS GTX970 DC Mini. Just announced

Haswell Mini Tower

Well the main thing, is how big do we mean by tower. Here the enclosure size like the Cube is the big factor. And with something like this we expect something big enough but not server sized. The other factor is that trying to get 2 GPUs and reasonable coolers into it. The full build is at PC Parts Picker and you can analyze how the cost is going. Right now it is a $2100 box with dual SLI GTX970 and all the trimmings! Processor With the recent price drop of the 4790K from$340 to $300 at Neweggbusiness.com for instance, it is pretty much a no brainer. The part is Core i7 running at a stock 4GHz/4.8GHz, but overclocking to 4.8GHz is pretty standard. That's about the faster you can run. Enclosure Using PC Parts picker, I there is no way to search for liters of space (e.g. how small the case is), so I just turned down the number of external and internal drives assuming that the fewer the drives the smaller the micro-ATX mini Tower to get and the SG09 or SG10 seem like the best bet right now for fitting everything in. • Silverstone Sugo SG09 or SG10 for a better front panel. Runs cooler but is slightly larger at 23 liters. In the Silentpcreview.com both are quiet at 24dbA. Need to see if can fit dual SLI cards. The SG10 is a follow on with a nicer front. This thing does look very attractive as it support full ATX, full length cards. The limits are 165mm cooler height, 180mm long PSU, 13.3” long GPU cards 337mm. • Rosewill Legacy U3. This is a m-ATX case at 20 liters. It supports 264mm graphics cards (so it is tight) • * Corsair Carbide Air 240. This is a pretty roomy case with 120mm HSF, 200mm PSU (so full size) and 300mm GPU clearances but it is also big at 12”x10.4”x15.75” (315x265x400mm=33 liters). And it has room for 3x3.5” and 3x2.5” drives which is a mountain of capacity these days (what with 6TB 3.5” and 1TB 2.5” inch plus 500GB of m.2/msata on the board).$80.

• Bit Phenom M. 30 liters so it is bigger although they have announced a micro-ATX Bit Prodigy which should be better

Graphics Card

This was also a little hard to pick, the GTX970 seems like the best price performance right now but you can get it factory overclocked.
The main concern here is noise. The GPUs are actually the most power hungry and the fan noise can be incredible. Silentpcreview.com has looked at noise factors and recommends:

• ASUS STRIX GTX 970 OC. This uses their very quiet DirectCU cooling system. The main problem is that it is 280mm long, so won't fit into the case that we have.This is a very quiet card and the GTX 970 (much cheaper should perform the same). No sense in having a quiet machine and then incredibly loud fans.
• MSI GTX 97o Gaming 4G. This card is also supposed to be very quiet.

• If you are just looking for performance, there are factory overclocked (the GPU is stock 1.04GHz):

Networking

Hopefully the board has a mini PCI Express slot but otherwise, a USB 3.0 dongle in the back isn't such a bad option anymore. The main problem is most of the USB dongles really stink. But the D-Link isn't bad