Very low seq write speed (14MB/s) on Macbook Air Rev A and 64GB 1.8'' ZIF Kingspec SSD

Greetings,

My 2008 Macbook Air was slowing down to a crawl so I bought a 64GB Kingspec to spice things up. Just when I was unpacking it the hard drive finally succumbed. Fortunately I had a backup which I restored onto the SSD.

At first it seemed like things improved, but as soon as I get low on its humble 2GB RAM - which happens all the time with Lion, even surfing web - I get beachballs and even typing in terminal becomes sloooow...

I fired Blackmagic Disk Speed Test and although it shows 88MB/s seq read speed, seq write only tops at 14

I've seen topics on UDMA modes - it seemed like Thinkpad folks had problems with their write speeds limited at 30... Is my problem in the same realm or do I just have a bad drive?

Thanks.

 

Do you have Trim activated???

Btw, I have never heard of that brand. Which country are you living in?

 

You restored backup to the SSD, in that case it may be misaligned, what program did you use to do this?
To check alignment Aligning disk partitions to prevent SSD wear - MacRumors Forums
OR do a clean install of your OS. Please let us know

 

Ramgen,

I did not activate it... I will do it when I get home, Thanks for the advice.

Josea,

I restored to SSD from a Time Machine backup. That alignment thing doesn't make much sense to me... I will run GPTfdisk and let you know the results.

 

GPTfdisk output -

Disk /dev/disk0: 125059072 sectors, 59.6 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 15026E3B-8FEF-42C0-A9A8-E71CA10FC4CA
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 125059038
Partitions will be aligned on 1-sector boundaries
Total free space is 9108 sectors (4.4 MiB)

Number Start (sector) End (sector) Size Code Name
1 63 125049959 59.6 GiB AF00

And this is what Trim Enabler says -

The patch is active but Trim is not. I can't seem to detect your SSD though, to make sure Trim is enabled, check System Information.

My ATA device information -

KingSpec KSD-ZF18.6-064MS:

Capacity: 64.03 GB (64,030,244,864 bytes)
Model: KingSpec KSD-ZF18.6-064MS
Revision: 20120517
Serial Number: ZF18612092100013
Removable Media: No
Detachable Drive: No
BSD Name: disk0
Protocol: ATA
Unit Number: 0
Socket Type: Internal
Low Power Polling: No
Partition Map Type: MBR (Master Boot Record)
S.M.A.R.T. status: Verified
Volumes:
5400:
Capacity: 64.03 GB (64,025,547,264 bytes)
Available: 22.28 GB (22,276,128,768 bytes)
Writable: Yes
File System: Journaled HFS+
BSD Name: disk0s1
Mount Point: /
Content: Apple_HFS


Mystery has not been solved yet... still writing slow and dramatic decrease in performance when low on RAM.

 

Ramgen,

I'm in US, according to http://forum.notebookreview.com/sol...orage/531052-1-8-zif-pata-ssds-available.html Kingspec doesn't support Win7 Trim. Does that mean, it doesn't support trim with OS X either?

 

I am not an OS X expert but if it doesn't support trim with Win7 then it shouldn't support with any operating system. And that explains why your performance degrades over time...

--

 

Thanks Ramgen,

I'm not sure about degrading over time, I just installed it.

The thread I already referenced mentions that ' Some SSDs don't have TRIM support, meaning they rely on garbage collection to maintain write performance. Use Tony Trim to help GC along.'

I'll try to find out more about it.

 

I could not find out how to use Tony Trim on Mac. The question is still open.