We’re big fans of Corsair’s Obsidian Series 650D. The case has earned choice spots in many of our system guides, and we’ve used it for a number of other projects, including our build guide and the personal PC build of our own Geoff Gasior.
Our affection for the 650D isn’t misplaced. The case is roomy, elegant, very comfortable to work in, and packed with nice little extras. It’s got a top-mounted drive dock, a built-in fan controller, and latched side panels that slide in vertically and click into place without so much as a thumb screw. There’s hardly anything about the 650D that we don’t like.
Except, that is, for its price. At $189.99 before a $20 mail-in rebate at Newegg, the 650D lies out of the reach of many budget-conscious builders. The steep asking price was the main reason I ended my review of the 650D on a lukewarm note back in May 2011. There may be much pricier cases on the market, but there are also far more affordable ones.
Now, over two years later, Corsair has introduced what it calls a successor to the 650D. Dubbed the Obsidian Series 750D, the new enclosure is bigger and roomier than its predecessor, yet it’s also more affordable, with a suggested retail price of only $159.99. What has Corsair improved, and what has it taken away in order to hit the lower price point?
Let’s find out.
Hmm. Interesting. The 750D looks familiar, but not in the way you’d expect.
At first glance, this enclosure seems like less of a re-styled 650D and more of king-sized version of the microATX Obsidian Series 350D, which we reviewed last month. The 750D has the same kind of bezel design as the 350D. The front ventilation is hidden behind a solid, removable panel, and the front-panel ports are fully exposed rather than hidden behind a door. Other design peculiarities, like the centered power button and the 5/8″ gap lining the front panel, are the same on both enclosures. It’s a newer, cleaner look, and I quite like it. The huge side window doesn’t hurt, either.
Sadly, the 750D mirrors its microATX sibling in other ways, such as its omission of several upscale features from the 650D. Instead of latches, the 750D’s side panels are held in place by old-fashioned thumb screws. The top-mounted drive dock is gone—now, external storage can only be connected via the front-panel USB ports. And if we look around the back, we see that the holes for liquid-cooling pipes have to be punched in by the user. They’re no longer lined with rubber grommets, either.
Comparing the 650D’s spec sheet to that of the new 750D reveals other notable differences between the two products:
|Corsair Obsidian Series 750D|
|Dimensions (H x W x D)||22.1″ x 9.3″ x 21.5″|
|Supported motherboards||microATX, ATX, EATX, XL-ATX|
|3.5″ drive bays||6|
|2.5″ drive bays||4|
|5.25″ drive bays||3|
|Included Fans||2x 140-mm front intake
1x 140-mm rear exhaust
|Front panel I/O||2x USB 3.0
2x USB 2.0
|Max. graphics card length||18.1″ or 13.4″, depending on drive bay config|
|Max. CPU cooler height||7.1″|
|Gap behind motherboard||1.1″|
The 750D is taller and slightly wider than the 650D. The added internal headroom enables support for larger motherboards—EATX and XL-ATX—as well as one additional expansion slot, for a total of nine slots. Corsair has lopped off one 5.25″ drive bay, but it’s kept the number of 3.5″ bays unchanged, and it’s added four dedicated 2.5″ bays. I suspect those 2.5″ bays will be much more useful in a modern build than a fourth optical drive bay.
On the cooling front, the 750D replaces its predecessor’s 200-mm front intake fan with two 140-mm spinners, and it switches out the 120-mm rear exhaust for a larger, 140-mm fan. However, there’s no replacement for the 650D’s 200-mm top exhaust fan. The 750D just has an empty vent in that spot. Users are free to stick any number of cooling devices up there, of course, but they’ll have to bring their own.
Oh, and FireWire is absent from the front port cluster. I doubt that omission will cause much grief, though.
Sorry for throwing all those specs at you all at once, but I hope it’s becoming clear that the 650D and 750D are two very different products. In fact, given their differences, I’d say they should be viewed not as two iterations of the same product, but as two separate offerings aimed at different users. That’s the reality—and a look at store shelves will likely tell you as much. Corsair tells us the 750D isn’t a “straight out replacement” for the 650D. Both cases should co-exist in the market, at least in the short term.
A closer look
Now that we’ve looked through the key specs, let’s take a closer look behind those sleek black panels. And, you know, at whatever else there is to see.
That’s plenty of front-panel I/O for a $160 case. Corsair supplies the usual audio jacks as well as four USB ports—two SuperSpeed and two USB 2.0. The USB 3.0 ports connect to the motherboard via a dedicated header, unlike on the 650D, where you had a couple of pass-through cables with type-A plugs, which you were supposed to connect to the rear I/O cluster.
Just like on the 350D, the lower half of the front panel can be removed to uncover the (also-removable) dust filter. Simply pushing in on the top two corners of the panel detaches it. That mechanism is convenient when clearing dust bunnies away, but it can be a pain when lugging the case around. It’s easy to put your hand in the wrong spot and unlatch one side of the panel by accident.
Speaking of dust bunnies, I think the 750D is the first Corsair case we’ve tested that covers the top cooling vent with a removable filter. That’s a nice touch. Even the 650D leaves that vent open to the elements, making it all too easy for dust, crumbs, and the like to drop in and cling to the hardware inside.
The top dust filter is rimmed with magnetic strips, which makes removal easy. The filter is also simple to put back into place; it just kinda sticks there. The magnets are pretty strong, too, so accidental removal is unlikely. The top vent can accommodate various combinations of 120-mm or 140-mm fans—or, if you’re into liquid cooling, a humongous 360-mm radiator.
Unfastening the 750D’s left panel reveals the internals, which are roomy. Very roomy. Corsair has forgotten none of the usual ingredients. We’ve got a cut-out behind the CPU socket, a generous assortment of rubber-lined cable-routing holes, tool-less drive bays, a stealthy black paint job, and so forth.
Note the default fan arrangement: two 140-mm spinners at the front and one at the back. I’m no fluid dynamics expert, but it sure seems like that arrangement will result in positive air pressure inside the case. That, in turn, should ensure that air only comes in through the filtered front vents, rather than through eaves and crannies large enough to let dust inside.
A number of Corsair’s other cases, including the 650D, have more fans dedicated to exhaust than to intake, which tells me they probably have negative internal pressure. Coupled with an unfiltered top vent, negative pressure can make for a very dusty enclosure. That’s the case with the Graphite Series 600T that houses my own PC, anyhow.
The 3.5″ drive cages are the same as those inside the 650D and 600T. Each cage plays host to three removable trays, which can each accommodate either one 3.5″ hard drive or one 2.5″ SSD. The hard drives snap into the trays without the need for screws, but 2.5″ drives must be screwed in.
Out of the box, the 750D comes with its two cages mounted side by side. The cages are stackable, though, so other arrangements are possible. For example, you can stack the cages on top of each other at the bottom, or you can hang them from the 5.25″ bays at the top. The default arrangement is better for long graphics cards, but the stacked setups should make cable routing more convenient, especially for folks using large power supplies.
By the way, you can order additional drive cages from Corsair’s website for $9.99 a piece. As far as I can tell, users should be able to supplement the two default cages with an extra pair, for a total of a dozen 3.5″ bays. Three cages can be slotted in between the 5.25″ bays and the bottom of the enclosure, and a fourth one can sit behind the PSU.
A closer look—continued
Now, what’s going on around the other side of the case?
Mmm. Yeah, look at that matte black finish.
Ahem. Well, there’s definitely plenty of room for cable routing. Corsair leaves just over a inch of space between the motherboard tray and the side panel; coupled with the substantial surface area available, that means even storage-heavy configs should be relatively easy to keep tidy.
Speaking of storage, this is where Corsair puts the 750D’s four dedicated 2.5″ drive bays.
Those 2.5″ bays are tool-less, and they behave very much like the ones in the 350D, except for the fact that they’re not stackable. The bays have a plastic spring and a release lever to make drive removal easier, and they snap onto the side of the chassis without the help of screws. The snapping procedure is a bit awkward—but hey, it beats having to get in there with a screwdriver.
There’s even more going on under the case. Here, we find a removable dust filter for the power supply’s intake fan, as well as emplacements for two 120-mm fans (or one 240-mm radiator). Those last two bottom vents aren’t filtered, though, and populating them requires relocating the 3.5″ drive cages. Luckily, since the cages fit together and can be mounted just under the 5.25″ bays, there’s no need to remove any of them, even if you stick a big radiator at the bottom.
If the previous photos didn’t make it clear how frickin’ big the 750D is, this one should.
The 750D is so big that it dwarfs our ATX motherboard. For the most part, that’s a good thing. We didn’t feel cramped while putting together our system, and there was plenty of extra space to run cables and make everything nice and tidy. The only notable exception was the power supply; with the drive cages in the default position, there wasn’t a ton of room behind the unit. Moving cages around—or removing them altogether—is always an option, though.
Our only gripe with the 750D’s huge dimensions is that, depending on where your motherboard’s three-pin fan headers are located, routing the wires for the two front fans may be awkward. In our case, the wires were almost too short to route behind the motherboard tray. The pictures above show one of the wires going right across the belly of our SSD and reaching diagonally up toward the mobo.
We had no problem with the other cables, though. Even the processor’s auxiliary 12V power cable had an acceptable amount of slack when plugged in.
On the storage front, installing hard drives was as simple as snapping them to a 3.5″ drive tray and sliding the tray back into the case. The optical drive installation was similarly easy. We just removed the front cover and slid in our DVD burner until it clicked into place. To release it, we simply pulled the tab and pushed the optical drive back out.
The four side-mounted 2.5″ bays were also fairly simple to use, although they did complicate cable routing somewhat. We had to be careful, for instance, to run the fan wires between the cages rather than through them. Otherwise, taking the cages out would have required unplugging the fans first.
Minor niggles aside, building a PC inside the Obsidian Series 750D is pretty much like what you’d expect from working with a Corsair case. In one word: painless.
Our testing methods
Here are the components we used:
|Processor||Intel Core i7-2600K|
|Motherboard||Asus P8Z77-V LE Plus|
|Memory||4GB Kingston HyperX DDR3 SDRAM at 1333MHz|
|Graphics card||XFX Radeon HD 7870 Black Edition|
|Sound card||Asus Xonar DG|
|Storage||Samsung 830 Series 128GB
Samsung Spinpoint F3 1TB
Asus Blu-ray combo
|Power supply||Corsair HX750W 750W|
|CPU cooler||Thermaltake Frio|
|OS||Windows 8 Pro|
We’d like to thanks Asus, Corsair, Kingston, Intel, Samsung, Thermaltake, and XFX for supplying all this excellent hardware.
We tested using the following applications:
The tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to discuss them with us.
Temperatures and noise levels
We used AIDA64 to keep track of temperatures for individual system components (the processor, GPU, motherboard, and storage drives) throughout a 40-minute period.
We left the system idle at the Windows 8 desktop for 10 minutes. Then we fired up the Heaven GPU benchmark and left it running by itself for 10 minutes. We then added a Prime95 CPU torture test to the mix and left it running, together with the Heaven benchmark, for 10 minutes. Finally, we stopped both tests and let the system cool down for the final 10-minute stretch.
The Obsidian Series 750D was compared to Corsair’s Obsidian Series 650D with its fan controller set to the low setting. The other settings spun the fans needlessly fast and were much louder, even at idle, than the 750D. The low preset gave us the best apples-to-apples comparison between these two cases.
Here are the results, plotted as lines over time. You can click the buttons below the graph to see temperatures for the different components:
The plots above depict broad trends; we can also give you exact numbers. The bar chart below shows the minimum temperatures from the idle and cooldown parts of the run. It also shows the highest temperatures recorded during the two load tests.
The temperatures of our processor and GPU—the two most power-hungry components—were largely similar in the 650D and the 750D. The 750D did run a few degrees hotter here and there, but the differences were, for the most part, very small.
The only substantial delta was in SSD temperatures. That’s no great surprise, since the 750D’s dedicated SSD bays are behind the motherboard tray, out of the path of airflow. Users worried about keeping their SSDs cool always have the option of mounting them to the 3.5″ trays in the main compartment. I wouldn’t bother, though. 2.5″ solid-state drives are designed to operate within the toasty confines of notebooks, and they can withstand much higher temperatures than a paltry 29°C. Intel’s 335 Series drives, for example, are rated for operation at up to 70°C.
What about noise levels? We used our TES-52 digital sound level meter to measure those.
The 650D’s marginally lower temperatures come at a cost: much higher noise levels, especially under load. The 750D was comparatively much quieter, with almost no difference in noise levels between idle and load. My ears confirmed those findings. The 750D whooshed discreetly regardless of what was going on inside, while the 650D whined and moaned during our Prime95 and Unigine Heaven test.
Clearly, then, the 750D does a better overall job of cooling components quietly than its predecessor. That’s a little surprising, since the 750D lacks the 650D’s huge 200-mm fans, but it’s definitely great news for those of us on (relatively) tight budgets.
The Obsidian Series 750D is a difficult product to wrap one’s head around.
Its model number suggests superiority to the 650D, and indeed, it surpasses the older model in a number of ways. At the same time, the 750D lacks a number of its predecessors trademark features, and it has a lower, more aggressive price. Corsair bills the 750D as a successor to the 650D, yet it’s candid about the fact that the two products will likely coexist in the marketplace for the foreseeable future.
Happily, by spending a little quality time with the 750D and 650D side by side, we’ve been able to demystify things a little. The long and short of it is that, while the 750D may be lacking in the luxury department, it’s a very well-designed enclosure with delightfully quiet cooling and enough expansion to satisfy… well, just about anyone.
Just think about it. The 750D can be populated with an EATX motherboard, six hard drives, and four SSDs. There’s room for two additional drive cages, each one capable of accommodating three extra hard drives. You can fit up to eight fans, and there are emplacements at the top, front, and bottom for 240-mm or longer radiators.
You probably don’t need anywhere near that much headroom, of course. But even for a run-of-the-mill build, I’d be inclined to recommend the 750D over the 650D. The 750D runs much quieter, and I expect it will attract less dust over time thanks to its positive-pressure fan arrangement and filtered top vent. I don’t know that I’d trade those perks for a built-in drive dock and side-panel latches—especially considering the prevalence of third-party USB 3.0 docks and external hard drives nowadays.
If I had one bad thing to say about the 750D, it would be this: the thing feels… well, too big at times. Even with dual graphics cards and a four-drive RAID, you’d only be scratching the surface of the case’s expansion potential. Part of me wishes Corsair had gone with something a little more compact, perhaps saving enough on the material costs to bring back some of the 650D’s features. Then again, Corsair already offers a case for folks with more reasonable expansion requirements; it’s called the Obsidian Series 350D, and it’s another TR Recommended award winner.