in-win BL-631 case review – small, packed, and mostly quiet with decent airflow

On the lookout for a small case, capable of holding a typical small motherboard, I came across the IN-WIN BL-631. It’s a small case making it somewhat portable, it can hold a MicroATX motherboard, half-size video cards, 2 hard drives, and a standard CD/DVD-ROM drive.

Unfortunately, if you decide to actually utilize all those things, you’ll notice it gets very, very packed:

To be fair, other small form-factor cases are going to suffer the same problem. If you’ve never owned a small case though, this is certainly something to keep in mind. While the airflow characteristics can be surprisingly good, things get very tight.

Component Installation:

The case didn’t come with much. No instructions, just the case, power cord, and 4 plastic pieces which snapped together to form 2 stands.

I won’t lie – instructions would have been helpful. I got the case off, and was left looking at the black shroud that goes over the CPU for airflow reasons. Obvious as that was, getting the shroud off wasn’t as obvious. I pried it out (it’s plastic, so you can force it out).

Next I needed to get the motherboard in. You’ll probably notice the yellow/green tabs/levers in the above picture. I pushed them down but nothing happened. In any case, I slid the motherboard in just like I would on a normal system. The case has built-in bevelled standoffs, and comes with screws to secure the motherboard with (although 1 odd screw threads differently and doesn’t actually secure the board – it looks the same as the others though so if you’re not expecting it, you’ll be turning the screw in forever until you realize that it’s not the right size).

The CPU went in next. There’s ample room to work, so it wasn’t a problem. I hooked up all the front panel stuff to the motherboard – fortunately the USB and front audio plugs are actual plugs (not single-wires like some other cases). Easy enough.

Next up was the drives. Unfortuantely there wasn’t room to stick in the lower hard drive. “Hmm…,” I thought. “There’s no way to get the hard drive in if the motherboard’s in first, but if you do the hard drive first you’re not going to have room for the motherboard”. I then started playing with those green/yellow tabs some, and found that they push forward/back to unlock the drive bay frame. “Wish I’d noticed that earlier,” I thought. Oh well. I noticed the front panel cover coming off at this point and figured I’d remove it before it snapped.

The drive bay frame is actually well thought out. Flipping those tabs unlocks it, and it pulls right out. You then have ample room to get the drives in, hook up the connectors, and then slide it back in. Not only that, but it gives you piles of room to work on the motherboard.

Here’s a shot where I’ve disconnected it and have pulled the drive bay out some:

A bit more room to work, and the only way to get all the connectors plugged in when you start getting a mess of wires.


A few issues, ranging from minor to major.

Minor: First, cable management in general is pretty rough. Things are tight, you have to route certain things around the bay frame, and since some of the frame is sharp, you risk slicing open a wire. Since a sliced wire might cause a short, a fire, or simply some dead components, you want to be careful here. Second, the motherboard had to be pushed pretty hard towards the rear for the screws to line up. Something that undoubtedly contributed to one of the shroud issues I mention next.

Medium: The plastic CPU shroud.

1) There’s a “cutout” near where you put the CD/DVD-ROM drive for the wires, but it doesn’t extend out enough. If you’re using a SATA cable there’s a very good chance that you’ll snap the connector off if you’re not very very careful, so be meticulous about your routing, and bend where you have to. If worse comes to worse, you’ll want to cut/modify the shroud so that you don’t have stress on your SATA drive connector. You may notice that I have a 3rd hard drive in there instead of a DVD-ROM drive. With the proper mounting bracket, you can make the smaller hard drives fit more easily.

2) The next issue is that the shroud also presses really hard against the wires coming from the 24-pin motherboard power connector. With the H55M-UD2H Gigabyte motherboard I was using, I already had a problem with the power connector wires pushing up against the RAM when all banks were full, so this just exasperated the problem that much more.

3) Finally, the shroud has a section that flips to accommodate 2 CPU positions depending on what CPU you have (no instructions for this, but it’s easy to figure out). Even when swapped though, it didn’t line up perfectly with the CPU at first. I had to flex it quite a few times before it bent enough not to put pressure against the CPU cooler.

Exasperating the shroud issue is that if it’s already pushing on something, the drive bay frame will cause it to push that much more upon installation. Be careful.

Large: Case Flex. When the case is assembled, there’s no issue. However, when the top cover is off, assuming you’ve got a couple of drives in there causing weight, the case will flex significantly. Enough that you could damage your motherboard. I was fortunate in that I noticed the case warping as soon as I started to lift it. If you’re unfortunate, you’ll probably hear the motherboard cracking instead. Either be very very careful when moving it, or wait until the top cover’s on and screwed in before moving it around.

A couple other things worth mentioning…

The included power supply claims to be 300W – the most powerful supply that IN-WIN offers for this case. It was quite quiet and had a pretty low fan speed.¬†You get 2 cable-runs coming out of the supply – each has an older molex-style connector, and a SATA-style connector (one also has a floppy connector). If you use 3 drives and they’re all of the same type, you’ll need an adapter.

It’s very possible to put a half slot video card in there. I had one in for a time. Of course, that leaves even less room for the wiring, but it’s doable.

You can add an 80mm case fan. You might see it in the above 2 images towards the top – it just slides into a holder, no screws or anything. Just make sure the pile of cables right beside doesn’t hit/jam it. Even at a low speed setting, my Antec 80mm case fan was audible. Still, I’d strongly recommend using one if you’re using more than 1 hard drive, are using a hot CPU, or have added a video card.

Air flow itself is pretty well designed, although you might want to tape over the expansion bay slot holes. There’s an intake cut-out above the CPU, and the shroud directs that air out the back of the case. There’s another cutout above where you’d put a video card that allows intake air to come in over that area of the motherboard, and ideally the power supply pulls that air out. However, like I said, you may want to tape over the expansion bay holes so that you don’t have it pulling in the warm air that the PSU just pushed out.

There’s a small air intake at the front of the case, but it’s not likely to do anything unless you have another fan added – the PSU fan simply spins too slow to pull air from every single intake. Adding the extra 80mm fan does help, but otherwise you’ll want to tape up everything you don’t want serving as an intake.

Finally, a couple images of the finished product:

I’d recommend using the stand. You can lay the case flat if you want, but instructions weren’t the only thing IN-WIN forgot…. there also weren’t any rubber feet included to match the 4 areas moulded into the case for them.


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  1. thanks, that’s really helpful, expecially the hard drive install part.

  2. I bought another case in this series, it shows my case, as with this one, standing opposite the way you have it placed (PSU on bottom). I’m curious if standing it upside down has caused any problems because I think that the fan vent is misplaced at the bottom.

    Not sure if you even check this anymore but if you could let me know that would be very helpful.

    Thanks, your review was a lot of help.

    • Nick: it’s tough to say without seeing your case and the PSU.

      With the BL-631, the PSU is doubling as as exhaust vent for the case, and kinda needs to be at the top (if it were placed at the bottom, warm air would be trapped in the top unless an additional fan was added).

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