-=PCTechTalk=- Re: SATA power connectors

Can Of Worms ALERT!  He's going for the opener!  Run!!!     lol

Quote:
"Would they be dumb enough to put in more connectors than the p/s could 
support?"

Reply:
They would never view it that way.  From their perspective, it would be 
'dumb' of the user to think that using every available connector would 
always remain within the specs of the PS.  Remember, these folks have been 
at what they do for so long that they have little to no recollection of a 
time when they didn't know that power supplies are limited by the amount of 
available amperage on each individual rail.  If you have to think twice 
about what you just read, 'they' will not be able to relate to your 
perspective.  Luckily for you, I'm not so far embedded in that type of work 
that I've lost my ability to translate.     :)

Simply put, it doesn't matter what the overall wattage rating of a power 
supply happens to be.  What matters is how much 'juice' is available on each 
individual rail coming from that PS.  If you have three devices that each 
demand 6 Amps and you put them all on a single rail that only provides up to 
12 Amps, you're going to have problems.  Note that the term "Rail" does not 
mean a single collection of wires supporting up to 3 molex connectors.  The 
rails are determined INSIDE the PS and may mean two of those lines (for 6 
molex connectors on a single rail).  Each PS design is different with some 
of them providing multiple rails and others utilizing a single rail design. 
Your task is to figure out just how much juice each of your devices needs, 
break them up on paper to make sure you're distributing power as balanced as 
possible (not 3A on one rail with 16A on another) and then buy yourself a 
power supply that can support all of it and still leave you some room for 
future growth.  The actual breakup of power among rails is provided by the 
PS makers on their respective sites, although it's not necessarily easy 
reading material.

This may mean that it takes an 800W power supply to give you the 450W of 
power you need because only the 800W PS will provide the necessary Amps 
across the main molex/SATA rail or rails.  Confused yet?  Most modern video 
cards suck up a LOT of amps, but not all PS makers internally separate the 
6&8-pin supply lines from the rest of the power feeds.  If your video card 
needs everything that a single line can give, you'll need to make sure the 
rest of your components do NOT get their power from any lines connected to 
that same rail.  Any setup that ignores this advice WILL provide the owner 
with hours of fun trying to track down faulty drivers, bad hard drive 
sectors, corrupted files, etc. and will leave them scratching their heads in 
total frustration since the PS is one of the very last things considered by 
most.

As you can imagine, there's a LOT more to this topic (such as efficiency 
ratings, heat loss, etc.), but I'm sure you're already glad you asked this 
question.  We're right here if you want to break it off into another thread 
to continue it.      ;^)

And now onto the rest of your post.

1.    You can use adapters to convert molex power connectors to SATA, but 
make sure there's enough juice available for all of the things you want to 
put on those rails.

2.    My current favorite external enclosure is the Vantec NexStar3 3.5" 
SATA to eSata / USB 2.0 Aluminum HD Enclosure.  It's available in a variety 
of colors (I have the dark blue), houses a single SATA drive and allows you 
to connect to your system using either a USB or eSATA connector.  Cost is 
under $30 US.  If you have the option to use eSATA, make sure you use a 
jumper to drop the drive down to SATA I mode (150Mb/s transfer speed) or it 
won't work with most motherboards.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817392002

3.    Go with the external as it gives you more options (easily moved 
between systems, no power needed from the host system, easier to replace the 
drive if necessary, can be used to test multiple drives without 
disassembling the main system, etc.).  Thumb drives use very little power, 
so don't worry about how your PS reacts to them.

Peace,
Gman

"The only dumb questions are the ones we fail to ask"

----- Original Message ----- 
From: "Don" <dsw32952@xxxxxxxxx>
To: <pctechtalk@xxxxxxxxxxxxx>
Sent: Saturday, January 31, 2009 12:41 PM
Subject: -=PCTechTalk=- SATA power connectors


>I have two SATA hard drives in my old Dellfromhell computer.
> I have no more available SATA power connectors available in my new HP. 
> They are used by the Hard drive and DVD drive.  There are several 
> available standard power connectors available.
>
> Do I need to get an adapter?  I know the drives have standard power 
> connectors on them (one has a plastic cap on it for some reason...maybe 
> not able to use it?) and those can most likely be used, but is there any 
> advantage to the SATA style connector that might prove beneficial?  other 
> than being easier to connect and disconnect.
>
> Also, I may need to buy an external case to use the other SATA drive. 
> Cheap is good.  On/Off swith is nice.  External power supply is VERY good 
> as I have a small P/S in the computer.  But....
>
> If the 300 watt PS can handle the drive I would rather mount it 
> internally.  I would have three hard drives, DVD drive, an external hard 
> drive which has its own P/S, and one or two thumb drives all connected at 
> once in addition to the usual stuff inside (everything is integrated in 
> the mobo so expansion card are present).  Would that overtax the P/S? 
> Would they be dumb enough to put in more connectors than the p/s could 
> support?
>
> Don
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