SATA PCI controllers

the_new_mr

Hi everyone.

Quick question here.

I've been dying for some extra hard drive space for ages now. Since my mb is a bit old and doesn't have SATA, I first looked at prices for a nicely sized IDE drive and found that they were way more expensive (per GB) than a SATA. So, my cousin suggested getting a SATA drive and a SATA controller PCI card. Lots of people on the net have been very successful with this kind of setup (most use it to expand on their mb's SATA ports if they want more hard drives or even to have extra IDE since a lot of new mbs only have one IDE port).

Anyway, I found one of these cards in a shop but the transfer rate was only 1.5 Gbps. My cousin said that I should try and find one that's SATA II (yes, I know it's not really supposed to be called SATA II and it's only really the 3.0 Gbps standard) so as not to miss out on the extra 1.5 Gbps transfer rate and that there was the possibility (although he's not 100% sure about this) that newer SATA drives may not work at all at the slower data rate with not all hard drives able to limit their speed through jumper settings and, even if they do, they don't always say how clearly on the drive itself (and even if they did, it would be a shame to miss out on all those extra bits per second).

So, what I'm asking is:
Does such a card exist (a 3.0 Gbps transfer rate SATA PCI card that's not PCI-E)?

Standard Toaster

Even the fastest desktop hard drives barely saturate a SATA/150 link

Here's a PCI one:
http://www.komplett.ie/k/ki.aspx?sku=354386



Read here re backwards compatibilty

the_new_mr

Thanks for the links man.

So, you're saying that there's no way a hard drive would actually need a 3 Gbit/sec card? I'm a little confused as to why the standard even exists if there are no hard drives capable of this.

Are there no 3 Gbit PCI cards anyway? Just all 1.5?

Standard Toaster

SATA-300 = 3 Gbit/s...or 3000 Mbit/s is 375 MB/s
SATA-150 = 1500 Mbit/s...or 187.5 MB/s

Ok, so that's that max transfer speed the 2 SATA standard allow. I'm sure you can subtract a few percent for overhead.

Now, the buses:
PCI @ 33mhz = 2133 Mbit/s...or 266.7 MB/s
PCI-E (x2) = 4000 Mbit/s...or about 500 MB/s


From wikipedia:
The theoretical burst throughput of SATA/150 is similar to that of PATA/133, but newer SATA devices offer enhancements such as NCQ which improve performance in a multitasking environment. Data transfer rates are limited by mechanical hard drives themselves, not the interfaces: the fastest modern desktop hard drives transfer data at a maximum of about 120 MB/s,[2] which is well within the capabilities of even the older PATA/133 specification.


So you see, it's the harddrive that's the bottleneck here. I'm sure a 10,000 rpm Raptor drive from Western Digital might hit the SATA-150 limit (around 130Mb/s) if pushed

the_new_mr wrote: »

Are there no 3 Gbit PCI cards anyway? Just all 1.5?

No point....PCI bus would be a bottleneck

the_new_mr

Great post there man. Thanks Edge.

Guess I'll just go for the 1.5 Gbps card then. Should save me money too

sink

the_new_mr wrote: »

So, you're saying that there's no way a hard drive would actually need a 3 Gbit/sec card? I'm a little confused as to why the standard even exists if there are no hard drives capable of this.

The next generation of Hard drives are called SSD's (Solid State Drive) they use flash memory as opposed to magnetic disks but are prohibitively expensive atm. They are able to use the full SATA II bandwidth and will completely replace magnetic hard drives in the future.

the_new_mr

News to me!! I need to start reading up on my technology again!!

Sounds cool!!