iMac 2007 intel 520 ssd, slow speed

[gobr]

Hi all, a bit of a blast from the past. I have installed Intel 520 SSD 180GB in my trusted iMac 2007. It's a hugely capable machine for everyday work and incredibly quick under Snow Leopard. In hope to get Mavericks as snappy as possible I tried the SSD solution. But it did not feel as fast as I was hoping. I then tried a benchmark and I got both read and write speeds in Blackmagic of 120-140MB/s. I know it is a 3Gb/s SATA but I am still away from the limit. The drive itself, under different benchmarks in Windows, is in the 400-500MB/s range. The trim is enabled using Trim Enabler.

Can anybody provide some numbers for any SSD installed in an iMac 2007? Would be great help to know whether it is as it is or I can improve on the speeds somehow. Thanks.

Edit: Forgot to say it is a 24" iMac 2007.

 

[Fancuku]

There were some SSDs that would operate under Sata I speeds instead of Sata II with 2007 and 2008 Macs. I wonder if the Intel 520 is one of them.

 

[gobr]

Thanks. This is interesting, this is the first time I hear of this possibility. It still says 3 Gigabit in the HW info. I found only one set of numbers for iMac 2007 so far. It was a 128GB Samsung 830 SSD and it achieved read and write speeds of around 250MB/s, also in the blackmagic test.

If I could now only compare an intel SSD performance on a 2007 iMac to my numbers then I'd be sure if another drive could work better. Almost there.

 

[peglegjack]

Thanks. This is interesting, this is the first time I hear of this possibility. It still says 3 Gigabit in the HW info. I found only one set of numbers for iMac 2007 so far. It was a 128GB Samsung 830 SSD and it achieved read and write speeds of around 250MB/s, also in the blackmagic test.

If I could now only compare an intel SSD performance on a 2007 iMac to my numbers then I'd be sure if another drive could work better. Almost there.

I have a 2007 iMac with a 120gb SSD, and I get about 260mb read and about 160mb write. This is using an OCZ Vertex 3. I also use TRIM but through the OS. Trim enabler isn't needed anymore.

 

[gobr]

Thanks for the reply. So I can hope for higher numbers if I find another SSD drive. Now I know of two types (OCZ, Samsung) that can provide the expected speed. With those numbers I can still hope to get Mavericks to be the primary OS.

 

[peglegjack]

Yeah, I mean I've never been knowledgeable about what drives give the best speeds for certain models, especially now. I just knew the one I have was SATA 3, while the iMac is SATA 2. I will say that I've run every OS on this machine since Tiger, and it runs as well as it ever has on El Capitan.

 

[gobr]

Perhaps it is just bad luck with Intel SSDs. But it is good to know that I can achieve nearly twice my current numbers. If I get my hands on a Samsung or OCZ I will give it a go.

 

[bent christian]

Samsung is making some of the best consumer-grade SSDs on the market today. I use two of them. I won't take chances with anyone else.

Keep in mind that, like a spinning hard drive, more dense SSDs will be faster. That is to say, less than 250GB will almost always be slower than 250GB and above. 512GB is often faster than 256GB (but not always), and 1TB is usually the same 512GB SSD doubled, so often no speed increase there. 120GB, or 180GB in your case, will nearly always be slower than something around 250GB due to the less dense grouping. This might be your problem. I use the Samsung EVO 850 256GB model in a Thinkpad that runs the drive on a SATA II bus and get around 300MB/s. My suggestion is to buy something bigger. The brand might not be the issue, but the density/size of the drive. That being said other factors such as write leveling and garbage collection come into play as well when choosing a drive. These affect longevity. When the difference can be as little as $10 or $20 between an OK drive and the best in class, I don't see a reason to be frugal.

 

[gobr]

I am aware of that, but I don't think that is the problem. The same drive is in the 500MB/s range on a newer PC with Windows. Besides, peglejack reports much higher numbers than mine on a 120GB drive. And a Samsung 830 that I found shown on Youtube achieved 250MB/s on a 2007 iMac. The price on this intel I have was unbeatable, it was free. Perhaps I'll find a Samsung for free as well. It is not that this Intel SSD is not doing its job, Snow Leopard is even better with it. So I do not truly complain. I will keep it, of course, but it is good to know that even more can be drawn out of this machine.

 

[peglegjack]

Is it a new drive? If it's been used, there's a chance that degradation has caused the read/write speeds to slowly decrease.

I would maybe try to do a secure erase on it if at all possible. It's what I've done with my SSD using software OCZ provides. I do it once a year, because the speeds always got slower with time, though with TRIM I may not need to do it anymore. I haven't done it since October and it seems just as fast as when I did the last secure erase.

 

[bent christian]

Is it a new drive? If it's been used, there's a chance that degradation has caused the read/write speeds to slowly decrease.

I would maybe try to do a secure erase on it if at all possible. It's what I've done with my SSD using software OCZ provides. I do it once a year, because the speeds always got slower with time, though with TRIM I may not need to do it anymore. I haven't done it since October and it seems just as fast as when I did the last secure erase.

Secure erase is not a good thing to do to SSDs. You are writing to the drive and effectively reducing it's lifespan. TRIM tells the OS which blocks are free, this is a completely different thing.

 

[gobr]

It still points out to this SSD type vs. mac. The disk produced the mentioned 500MB/s on a Windows PC just days before being formatted and used on the mac. The sandforce controller in those intels prefers compressible data as it does compression on the fly. So the specifed numbers are always reached with compressible data. Blackmagic uses highly compressed files so the numbers are somewhat lower. But again, not half of the speed is lost there. Too bad the drive in imacs is in such a difficult place to reach. Otherwise I could try Samsung from my main machine just to see the speed.

 

[peglegjack]

Secure erase is not a good thing to do to SSDs. You are writing to the drive and effectively reducing it's lifespan. TRIM tells the OS which blocks are free, this is a completely different thing.

Cool, yeah thanks for letting me know. I still don't regret doing it honestly, mainly because TRIM wasn't supported on 3rd party SSDs at the time and it always made my drive dramatically faster. But now with TRIM, I probably won't do it again. In any case, I'm not taking the drive out of this iMac anyway (too much to deal with at this point) and I'm sure it'll last however long I need it to.

 

[gobr]

I found the main problem, but not quite the cause of it though. My negotiated SATA speed is only 1.5GB/s, most of the time. Occasionally it is 3GB/s in Snow Leopard. I've caught it like this some minutes ago and did a benchmark in Xbench. I got read and write speeds in the 220MB/s range, which is what I expected initially. Then after a reset, or even after a shutdown it mostly ends up in the 1.5GB/s negotiated speeds resulting in speeds of 120MB/s. In Mavericks it only boots with 1.5GB/s speed. I found one forum where a person experienced this after upgrading from Mountain Lion to Mavericks. Resetting PRAM does not help.

The cause is not known. If anyone is interested here is some info about sandforce controller and nvidia SATA controllers, which were common for early intel iMacs. Most of that is experience based with no clear conclusion.

https://forums.macrumors.com/threads/ssd-upgrade-on-2008-imac.1433551/
http://blogs.helsinki.fi/tuylaant/2014/01/upgrading-old-macs-to-ssds/

But my SATA controller (the one in the iMac) is Intel. That only leaves sandforce controller as the common denominator in reported issues. There is not much data as not many people are running old macs with SSD and reporting problems.

I could see that Samsung consistently works well, I could not find anyone reporting problems with 830 and 840 series. So if I get my hands on one of those I'll give it a go.

 

[bent christian]

Current Samsung SSDs are the 850s. This is what you want. I don't think the 830s are in production anymore. I can't see a reason to buy an 840, as the controller has been upgraded since then.

If you are going internal, buy the EVO series. You won't be able to max out the write speeds on SATA II and TRIM will be supported. The "Pro" series uses the improved MEX controller. It has better write leveling and possibly better GC. This will be important if no TRIM is supported. If you are booting externally, I'd recommend you go with that. It is what I use.

 

[gobr]

Yes, sure. I meant that whatever comes for a reasonable price, this is an old machine and investing money into it does not make much sense. So if a used 830 comes along I'll take it.

I will investigate more my current situation. People have noticed issues with Intel 520 and nvidia sata controller in the mac, but not with intel controller which is exactly my problem.