SSD Drive VS SAS 15,000rpm Drives

[Will Keir]

Hey guys, looking for a little advice on a Mac Pro system I had:

3x 15,000 rpm SAS 450GB promiss Raid 5 w/ Apple RAID card

It was 5x faster than my 7,200rpm standard SATA drive.

I am wondering how a 512GB SSD compares in speed to the (3x 15,000 rpm SAS 450GB promiss Raid 5 w/ Apple RAID card) as mentioned earlier.

This system I build was incapable with BOOTCAMP because of the raid card, it couldn't switch between SATA and SAS.

Can SAS drives with an Apple RAID card work with bootcamp if I use a SSD Drive?

[Christopher Barrett]

I've used SSDs (from OWC) in my tower as single drives and in RAID 0. Was able to use both options as boot drives. SATA, though, not SAS. My Max speed with the RAID 0 was around 600mb/s. The SSDs were limited slightly by the SATA max limit. I have an 8 drive (7200RPM) RAID 6 now via SAS. I get about 800mb/s out of that. Not bootable but wicked fast. I like the SSDs for Boot drive and the SAS RAID for storage. Even a single SSD at around 280 mb/s yields a pretty snappy OS.

I don't have an Apple RAID card, so can't comment, but hope this was helpful.

[Will Keir]

If I remember correctly the Apple RAID card over rides the booting process. I could install a SSD for the boot drive and make the other 3 SAS drives RAID 5. That is "IF" I can dual boot windows/mac with a Apple RAID card installed. That's the question I'd really like answered. Thanks for the input.

[Will Keir]

A bit more research, the SAS drives require a RAID controller.

I would be happy using SAS drives and RAID controller in Mac OS X.

Then have a SSD drive for windows and boot off of that. But is there a way to boot at SSD with a RAID controller installed, even if I am not using it for the windows side?

[Jeff Kilgroe]

Apple RAID card is junk. Sorry, but it is. And yes, you can boot from it. Then again, you can boot from any good RAID card -- ATTO R6xx, ARECA 18xx...

SSDs currently are not a great solution for RAID. For starters, you can saturate most RAID interfaces with HDDs just fine and at lower cost. Not to mention, most all SSDs rely on internal or on-the-fly compression to boost data rates. When you transfer large files that are non-compressible such as R3D, H264, et.., you will see a sharp drop-off in your data transfer speed. SSD's are the way to go for boot drives, app storage, that sort of thing. For larger volume RAID storage and workspace, HDD RAIDs still hold the crown.

10K and 15K rpm drives offer a nice performance boost, but at the expense of smaller capacities and higher prices per GB. While you do gain improved seek times on these drives due to the faster spindle rotation and lower relative data density, that advantage fades with increased numbers of drives in a RAID set. The 3.5" 15Krpm drives also suck a good bit more power and are louder while operating than their 7200rpm counterparts. IMO, the best bang for the buck is still a conventional RAID made of 7200rpm drives like the 2TB WD RE4 series.

You can't use BootCamp with the Apple RAID controller, period. It doesn't matter if you use SSD or HDD, SAS or SATA. It's the controller that is the issue.

In terms of speed the 3 x 15Krpm 450GB drives should still be a good bit faster than the SSD in all areas but seek time, which is near instant on SSD. If you want to use BootCamp on your system, you need to put the Windows / Linux partition on a drive not connected via the Apple RAID system -- such as mounting it in the lower optical bay. Pain in the ass, but that's just how it works.

[Will Keir]

Apple RAID card is junk

You said it. That little junk card came with all sorts of trouble but none technical. I spent another $2k on these SAS drives that cannot work without it and this configuration that does not allow me to use boot camp.

[Will Keir]

Your post gives me a little hope, so please shut me down if I'm just wishing.

Can I add a SSD Drive to the optical bay and use it only for windows without removing the RAID card? I would use the SAS RAID 5 set of drives for Mac OS X.

Can I OPTION boot and be able to selected the SSD or SAS RAID system. I know I was not able to do this with SATA drives in bays 1-4.

[Will Keir]

You can't use BootCamp with the Apple RAID controller, period. It doesn't matter if you use SSD or HDD, SAS or SATA. It's the controller that is the issue.

If the SAS drives with RAID card are not using bootcamp but the SSD I install is, can I make this system work that way?

Jeff, thanks for taking the time to read my post and for being helpful, even if the solution I so stubbornly want, might not be in the cards. Looks like I need to figure out what to do with the SAS Drives +RAID card and buy some SSD's and use SATA in the 3 open bays.

[Jeff Kilgroe]

When you install the RAID card it takes over the 4 drive bays in the system. They can be configured individually or in various RAID configurations, but boot camp (and therefore Windows) is not compatible with the RAID card. You've already found that out on your own. :(

However, YES! you can install a SSD or HDD in one of the optical bays and you can boot from it! The two SATA channels that go to each of the optical bays are independent of the RAID card. I want to say that bootcamp will work in this situation and I'm 95% sure that it will. I have Bootcamp on a Mac Pro with the Windows partition on a drive in the lower optical bay. No problem there. However I have not set up boot camp on a system with the Apple RAID card installed, even though the bootcamp drive would not be connected to it. So... I *think* it will work, but not sure. If you have your lower optical bay open, throw a spare HDD in there (f you have one) and see if it will let you set up a bootcamp partition on it!

My biggest complaint about the Apple RAID card wasn't really the boot camp issue, but the very poor management system. the battery backup on Apple's RAID card is one of the dumbest implementations I've ever seen. It attempts to test and condition the battery every now and then (which is a good thing), however it likes to pick seemingly random intervals on which to do this and it doesn't let you abort or schedule that operation. While it's doing it, your RAID is slowed to a crawl and becomes borderline unusable for the duration of the process lasting several hours. This was the number one complaint with it for more than a year after its initial release. I don't know if they've ever addressed that issue with the revised modle for the '09 and newer Mac Pros. But I don't see as many complaints about the battery system these days.

You can run SATA drives on the RAID controller, doesn't have to be SAS. However, all drives connected to those four drive trays must be of the same type, either SAS or SATA, you can't mix them. That's normal amongst SAS/SATA controllers.

[Will Keir]

Well long time issue, perhaps finally solved. I have a SATA with boot camp already on it, so I can test this and see how I do. As far as installing the SATA in the #2 optical bay, that should be easy enough to find online, thank you again for all the help Jeff.

I'll post back with results for others interested in this topic.

Best.