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Maximus 5 Extreme - very slow SSD speed on mPCIe Combo

WillyK
Level 10
My Win8 System (boot) disk is an Intel 525 SSD mSATA 240G SATA III drive (SSDMCEAC240B301) mounted on the mPCIe Combo. It generally should provide up to 550/520 MB/s (read/write).

However, I'm experiencing less than 70/14 MB/s on this drive which of course is ridiculously slow...
It also shows clearly in the WEI by scoring only 7.8 of max 9.9 (Win8), while all other components are rated 8.4-8.5!

I'm currently using several Intel 520/525 SSDs and all are lightning fast, but the one on the mPCIe Combo. I've used the Intel SSD Toolbox to check the FW, trim and optimize this SSD without any improvement, so I assume the problem has something to do with the mPCIe Combo or the MoBo itself.

Anyone experiencing the same kind of issues?
Any ideas about how to fix this?


UPDATE:
I apparently misread the Asus mPCIe mSATA specification: SATA 3.0 Gb/s as ... SATA 3 ...
(What can I say. S... happens.)

That explains some of the reason, but still it's too slow in my opinion.
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9 REPLIES 9

Praz
Level 13
The mPCIe slot is 3Gb/s. You won't see 6GB/s performance numbers from the drive connected to this slot.

WillyK
Level 10
I see that the new mPCIe Combo II card for the Maximus VI Series boards is supporting SATA III (6 Gb/s).

Is it possible to install the Combo II on a Maximus V Extreme?
If so, can I buy the Combo II card separately, and can I reuse the WiFi chips from the original Combo that I have now?

Praz
Level 13
The Maximus VI series like your Maximus V uses a single 2.0 PCIe lane for the Combo card connection. Regardless of marketing claims a single PCIe lane does not provide the necessary bandwidth for full SATA 6Gb/s performance.

WillyK
Level 10
Figures... Thanks Praz.

Btw I asked the same question to Asus VIP Support and here's the answer I received:
"We haven't done any official testing of this and as such i can't confirm anything. I recommend you check online and see if other people have gotten it to work."

I've already moved my system to a discrete SSD and the WEI rating for Disk immediately went up to 8.3 ... (of course, it's noticeably faster too)

Praz
Level 13
Because of board layout ( most all motherboards) there really isn't a reason to be using mSATA compared to connecting a SATA 6Gb/s drive directly to one of the native SATA 6Gb/s ports. Marketing claims don't make this readily apparent though.

Praz wrote:
Because of board layout ( most all motherboards) there really isn't a reason to be using mSATA compared to connecting a SATA 6Gb/s drive directly to one of the native SATA 6Gb/s ports. Marketing claims don't make this readily apparent though.


Would the same be true of using say the new RAIDR Express? would they even be able to soak up enough lane throughput to hit their claimed speeds?

Praz
Level 13
The RAIDR Express uses 2 PCIe lanes and because of the architecture should have less overhead than mSATA. I'm guessing somewhere around 800MB/s read/write benchmark speeds should be achievable. This is assuming a PCIe slot from the CPU and not the PCH is used.

Praz wrote:
The RAIDR Express uses 2 PCIe lanes and because of the architecture should have less overhead than mSATA. I'm guessing somewhere around 800MB/s read/write benchmark speeds should be achievable. This is assuming a PCIe slot from the CPU and not the PCH is used.


Fair enough, thanks for the info! 🙂 +1

Praz
Level 13
It will be interesting to some results once these drives become available.