Overall: Both are great enclosures but because heat is a real issue the faster the drives run, they are both bigger than previous TB4/USB4 drives. Be prepared for the larger size and in the case of the Acasis enclosure, noise from a fan. You will get extreme speed from both and the overall performance difference between them is negligible. The OWC is weather-proof with a great seal, but also has a captive cord, which personally I find annoying. It seems to be they could have made it just a weatherproof without the captive cord, so I'm not entirely sure of their justification for this design choice. The price is basically a wash as the Acasis is quite expensive IMO; it has a slight edge in that you can use a pretty cheap NVMe drive if you want, but ultimately for the best performance you shouldn't be using one of the cheap drives anyway. The Acasis comes without a drive, and you there are no warranty issues (obviously) installing your own. I of course just opened up the OWC case and put my own drive in there. According to OWC they didn't make it with an 8TB drive due to thermals and voltage, but I've been using it with an 8TB Sabrent TLC NVMe drive for about a month with zero issues.
Size: Based on volume I'd guess both are similar in size; the Acasis is thicker to fit the fan in there, but shorter and narrower than the OWC. I can't really say I prefer either style. Honestly I think a passively-cooled version similar in design to the OWC Express 1M2 would be fine for a TB5 enclosure with enough thermal mass from the aluminum body and fins to dissipate the heat, but obviously that would need to be tested by the manufacturer. The attached cord mentioned above is a negative for the OWC drive for travel.
Heat: They get warm, both of them, but it's not really hot unless you are doing a long sustained transfer of a huge amount of data. That's honestly something that's pretty infrequent in most usage unless you are using it for storing raw video footage and then it could be something to think about, although they both have been designed to make this not a problem. For photographers, even copying 20-30,000 files takes relatively little time (I did a test and copied 4.6TB in under 15 minutes--that was about 85,000 A1/A9III raw files). The fan on the Acasis drive does seem to keep that case a bit cooler but it comes with a very slight whisper noise. Given that my MacBook Pro's are dead silent, I am not a fan of the fan.
For performance tests I used the exact same WD 8TB Black SN850X TLC NAND NVMe drive; I also compared it to a Sabrent 8TB Rocket 4 Plus TLC NAND drive; both are PCIe 4.0 drives with theoretical maximum transfer rates near the limit of what TB5 can handle. The WD is slightly faster overall and does better a longer sustained transfers. It's also less expensive so overall it's the better choice.
The bottom line: I personally have a pile of the older ACASIS 40Gbs enclosures that are much smaller. They get hotter due to the smaller thermal mass, and of course the top speed is limited. However, for most of what I am doing that speed is way more than enough. The same drives in those enclosures will hit around 3150/2900Mbs R/W on average. I run all of my Lightroom libraries directly from these drives. I don't see myself buying a lot of other 5TB enclosures right now because the trade-offs in size, price and or noise from a fan are really just not worth it for an increase in speed that has no functional benefit for me 99.99% of the time. But for those who really want that speed or need it (shooting lots of raw video for example) these would be a great choice. Sabrent announced one back in August but it's still not available. The original announcement showed a smaller fan-free design so if they release it in that form, that would probably be my default choice.
p.1 #3 · TB5 External Drive Comparison: Acasis and OWC
Great info and thanks for doing the test!
I'm curious about the 4.6TB transfer; how long did it go at peak transfer speed before the cache filled? And once that happened, what was the sustained speed? Was it the WD drive?
I think the cache is very dependent on available space and have noticed my SN850Xs in the Acasis TB4 enclosure can drop out of the highest transfer rate relatively quickly. But my drives tend to be quite full most of the time.
p.1 #4 · TB5 External Drive Comparison: Acasis and OWC
They seem kind of expensive compared to the TB4 enclosures but that is to be expected. What sort of platform were you running your benchmarks with the TB5? Also, how loud was the fan on the Acasis?
p.1 #5 · TB5 External Drive Comparison: Acasis and OWC
armd wrote:
They seem kind of expensive compared to the TB4 enclosures but that is to be expected. What sort of platform were you running your benchmarks with the TB5? Also, how loud was the fan on the Acasis?
All of these were run on my M4 Max MacBook Pro. That and the new M4 Mac Minis are the only computers out there at the moment with TB5 that I am aware of. Apparently there are two PC laptops with it, but both are cheaper brands and the one article I read testing them showed they were poorly implemented. As an aside, it's that kind of half-baked hardware that was one of the many reasons I left the PC world behind years ago and have never looked back.
The Acasis fan is pretty quiet...but like I said, when the MacBook Pro is absolutely dead silent, I can hear it. I've been spoiled the last few years with the Apple Silicon in my MBP's and the Mac Studios I use. They are all just dead silent and I love it.
p.1 #6 · TB5 External Drive Comparison: Acasis and OWC
rscheffler wrote:
Great info and thanks for doing the test!
I'm curious about the 4.6TB transfer; how long did it go at peak transfer speed before the cache filled? And once that happened, what was the sustained speed? Was it the WD drive?
I think the cache is very dependent on available space and have noticed my SN850Xs in the Acasis TB4 enclosure can drop out of the highest transfer rate relatively quickly. But my drives tend to be quite full most of the time.
Actually I hit send on that before I edited it. It was estimated at 15 minutes and was going along well and then stalled out. I was transferring between the Sabrent and the WD and the Sabrent has stalled out faster in the past. I'm going to do some more testing between two WD drives as well and report back. The cache is actually DRAM on the chip, and it's a great place for the drive manufacturer to save some money and power draw since a large DRAM cache isn't needed most of the time.
It took more like 25 minutes....which is still not bad for 4.6TB but not nearly as fast as it theoretically could be.
p.1 #7 · TB5 External Drive Comparison: Acasis and OWC
Hi, just a quick note to thank all the contributors to this forum, particularly jhapeman for all the great information.
It was time to move on from my 27" iMac. Settled on the Mac mini Pro, 1tb and 48 gbs ram.
Thanks again and a Happy New Year.
p.1 #11 · TB5 External Drive Comparison: Acasis and OWC
Thanks, yes, I tried the supplied cable, and all 3 ports on the back, and many other cables I have.
Tried other cables as well.
Anyway to hard reset the ports, other than power off/on the M4 ?
p.1 #12 · TB5 External Drive Comparison: Acasis and OWC
buggz wrote:
Thanks, yes, I tried the supplied cable, and all 3 ports on the back, and many other cables I have.
Tried other cables as well.
Anyway to hard reset the ports, other than power off/on the M4 ?
Interesting, I have one of the newer v2 Acasis closures that's thinner and has a fan you can turn off...and it shows the same thing plugged in. It's got the Intel TB5 chip in it, so I'm not sure why it's falling back to USB4 v2, but I also notice that Acasis isn't selling these as certified TB5 drives.
My OWC drive is at the office so I'll see what it says when plugged in. Regardless, it is getting the max speeds possible when compared to the OWC unit using the same NVMe drives, so I'm not terribly concerned. But if it is running at USB4 V2, it does miss some bonus items you get with true TB5.
p.1 #13 · TB5 External Drive Comparison: Acasis and OWC
An important one to me would be temp. monitoring, though, I keep mine even cooler via USB powered fan.
I too am enjoying really fast speed from this enclosure.
jhapeman wrote:
Regardless, it is getting the max speeds possible when compared to the OWC unit using the same NVMe drives, so I'm not terribly concerned. But if it is running at USB4 V2, it does miss some bonus items you get with true TB5.
