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eSATA Connectors
buffalocheese writes "Since the introduction of the Serial ATA 1.0a specification in 2002, many manufacturers have introduced PCI and CardBus cards with both internal and external SATA connections.
At first these internal and external connectors were completely identical, but later, external connectors started to appear which were still fully compatible with the internal sockets but featured added extra screening for external use.
With the introduction of the SATA II specification in mid 2004 a new external SATA connector was defined. These new external (eSATA) connectors are not compatible with the original internal SATA connection.
Currently there are add-on cards and drive housings available which feature both types of SATA connection for external use. Gradually the older types will disappear and all new SATA cards will feature the eSATA connector for external drive connections."
Frankly, I'm not a big fan of the current SATA connectors. They tend to fall off at the slightest provocation. I can't work in my case without having to check at the end that all of the SATA connectors are still in place (and at least one of them is usually loose or completely off). Because of this I've been reluctant to switch to SATA on external enclosures. If this new connector can prove itself resistant to falling off, it may in fact be a winner (I would even advocate unifying the connectors again under the new standard). I do like the fact that both the external and internal SATA connectors are currently the same, I just don't like the connector itself. It's rather nice to be able to take an old AT power supply (the kind where the power switch is hardwired to the supply) and plug in an off of the shelf SATA drive to the back of my case in a pinch. Plus, fewer connector types means fewer adapters I'll eventually have to own.
I read the internet for the articles.
While I'm not as certain when it comes to graphics cards, PCI-Express is/was sorely needed to replace PCI for general expansion cards. PCI had a limited amount of bandwidth available that was extremely easy to saturate (A single gigabit NIC would hit a bandwidth wall at something like 400mbit). The shared nature of the PCI bus was also an extremely frustrating limitation.
By contrast, PCI-Express 1x slightly increases the bandwidth from roughly 133MB/s to 150MB/s, but more importantly each device gets that, it's not shared anymore. And of course, 2x and higher slots provide more bandwidth.
But when it comes to graphics, AGP 8x was (at the time) providing more than enough bandwidth... as for the demands of modern monsterous graphics cards (such as the 8800 GTX), for all I know they might be able to saturate an AGP 8x bus.
As I understand it anyhow, the more tangible benefits from moving from AGP to PCI-Express were increase bi-directional bandwidth (AGP was great at Host->Card, but sucked at Card->Host), and increased ease with sticking multiple PCI-Express slots on the motherboard, making modern SLI possible.
The official specs for eSATA essentially say the cable is better suited for external use. Here's what they have to say about it:
The external cable connector is a shielded version of the connector specificed in SATA 1.0a with these basic differences:
The External connector has no "L" shaped key, and the guide features are vertically offset and reduced in size. This prevents the use of unshielded internal cables in external applications.
To prevent ESD damage, the insertion depth is increased from 5mm to 6.6mm and the contacts are mounted further back in both the receptacle and plug.
To provide EMI protection and meet FCC and CE emission requirements, the cable has an extra layer of shielding, and the connectors have metal contact points.
There are springs as retention features built into the connector shield on both the top and bottom surfaces.
The external connector and cable are designed for over five thousand insertions and removals while the internal connector is only specified to withstand fifty.
They make it pretty clear exactly what's different. The biggest difference is the cable is shielded, while internal SATA is not (or less so?). And obviously the connector being rated for a hundred times more insertions is a pretty big difference.
I should note that in recent benchmarks done by MaximumPC, eSATA did not provide substantial performance benefits over Firewire800 drives. eSATA featured a higher burst speed, but more or less equivalent average transfer rates and seek times. Unless there were specific licensing issues with Firewire 800, I would rather have seen it become the preferred drive interface; I'll take a general purpose connector that I can use for other stuff over something as specific as eSATA any day, especially when eSATA provides little benefit.