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rwinter said:

Mike Wuerthele said:

rwinter said:

Mike Wuerthele said:

rwinter said:

This just in: my friend who got the 15" i9 variant with 32Gb of RAM and 512Gb SSD is also seeing ~1700Mb/s.

(Maybe it's just me, but this seems like a hugely important info)

The Blackmagic Disk Speed Test is designed to test/stress the SSD device the same way video does.  It does not seem to really indicate exactly what tests it is running (compressed data vs non-compressed, sequential read/write vs random access reading and writing, block size of the data etc).  SSD specifications (i.e. package specs) only tend to publish the specs that you will get the highest rating from...  which I believe is probably sequential read and then sequential write-only. 

I used Blackmagic because that's what I saw on most (if not all) of the reviews out there. If anyone has any other (free/open) suggestions, or other ways of testing the SSD speed, I'd be glad to try them.

Regardless of what the type of test Blackmagic does, shouldn’t it be consistent for all 2018 MBPs with the same capacity/number of NAND chips from the same vendor?

Exactly my thoughts. What's weirder is that the 512Gb 13" seems to reach the advertised 2500Mb/s (at least that's what I gather from the reviews).

Is there a way of knowing for sure the number of NAND chips on my machine?

Probably, though the question would be is there a difference depending on capacity.

The answer seems to be yes, unfortunately. It appears that for some (bizarre) reason the 13" gets two 256Gb in RAID0 and the 15" gets only one with half the speed (which would be total nonsense considering not only that the 13" is cheaper, but also that the 15" would be 'more pro').

I wouldn't mind it being slower as long as it were clearly stated on Apple Store's configuration page (I even looked for it before making my purchase! The only thing mentioned is the difference in capacity, never speed).

All in all, after holding back my purchase by the whole throttling fiasco, this is very frustrating. If I had been informed in advance I'd have gotten the 1Tb model, it's not only more storage it's twice as fast (apparently).

The 512GB i9 version we're publishing the review for shortly exceeds 2500 MB/sec.

How long have you had the machine? There is a pile of indexing the drive after a new user migrates data that can run for days, and this will impact SSD benchmarks.

I got it five days ago and I didn't migrate any data, plus I don't see mds or any suspicious processes running while testing the SSD. I even tried turning off FileVault (and saw no difference). I've even tried the test on different days before posting here.

There was a post a few days ago with the same results as mine and my friend's: https://forums.appleinsider.com/discussion/206400/ (that's the only mention I found online of a result similar to mine).

Huh. I'll poke about, see what I can find.

I'll try to go to an Apple Store tomorrow and see if they let me benchmark the Macbook on show (I doubt it though).

I don't know what else I can other than that.

Well, after going to the store, talking to people, making calls and doing a lot of different stuff... I got my MacBook replaced today. And the results are exactly the same!

My 512Gb SSD on the 2018 15" MacBook seems to be performing more slowly than those on the 13" model. It never ever goes past 1800MB/s write on Blackmagic Disk Speed Test. What is more puzzling is that the tests you (Appleinsider) made give different results (at least on the i9 15" model).

If anyone has any idea what's going on I'd love to have more info. I'm also attaching a screenshot of the NVMExpress session of "System Information.app" maybe that can be of interest (and could be compared to machines that perform better than mine).

Hey man not sure if you're still searching for answers but based on your post I took my Macbook Pro 15 inch in today and told them my drive wasn't going above 1700, which it wasn't.  They allowed me to switch it out in store for a better model.  Basically from my reading what I've found that the 512 gb SSD in the 15 inch shipped initially with Samsung SSD instead of Toshiba.  Apple is aware of the problem and acknowledging it with replacements.  If you want you should be trying to talk to someone about getting one of the models with the newer chipset.  The samsungs cap out at 1700, the Toshiba get to the 2600 speed.  Seems to really be affecting the 512 but not sure about the 256.  I upgraded to a 1tb tonight with more ram and mine is running at 2600+ . Hope that helps