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- 8-pin vs 4-pin 12V connectors
September 10, 2009, 2:04 am
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I've recently purchased a Gigabyte motherboard that as an 8-pin 12V
connector on it.
The case I would like use came with a power supply, that a 4-pin 12V
Can I just use an adapter to split the power supply leads, or can I run
into supply issues?
I haven't picked the processor yet, but I suppose I'll shoot for some
sort of Core 2 Quad. I have a low to middle video card, a Radeon HD 4650.
- - - -
As a related question, I see that Core 2 Duos and Quads (1333 FSB) are
running about the same price. Is there any reason, other than money, to
get a Duo over a Quad?
Any recommendations about a good price/performance saddle point in 1333
FSB LGA 775s?
Re: 8-pin vs 4-pin 12V connectors
When a desktop motherboard has an 8 pin (2x4) power connector, you can
plug a 4 pin (2x2) power connector into it, without a problem. The
user manual will explain which holes to use. Some motherboards come with
a sticker, covering up the extra four holes. That helps guide the builder
to the correct holes.
The presumed purpose of the extra pins, is for extra current flow. My guess
would be, a 2x2 would allow 144 watts at power inlet, enough to run a 130W
processor. You'd want a real 8 pin connector (8 wires leading back to the power
supply), if you were doing an overclocking experiment, like running a D 805 at
4GHz. That used to draw over 200W. So it is possible certain overclocking
experiments, may make good use of 8 pins. But for most sedate applications,
I would expect four pins is enough.
You would buy a duo, for situations where you wanted to save power. For
example, say your mom has a computer for email and web surfing. She doesn't
play Crysis all that much. She also hates to waste electricity. Then a
Core2 Duo can be pretty good on power. (I think my cheesy one, uses a small
number of watts, like 12W maybe, and I don't even have EIST turned on at
the present time.)
Otherwise, you might as well go with the quad.
The Intel quad, is two Core2 Duo silicon die, placed side by side, in the
same package. If a task bounces from a core on one die to the other,
some traffic would flow over the FSB. Some OSes apparently understand this,
and have some provision to take into account whether a task is moving from
one silicon die to another (Vista/Win7 ?).
In a "perfect scaling" test, an Intel Quad provides the performance of
about 3.5 cores. That means the FSB and cache arrangement, may steal
about 0.5 cores worth, in some scenarios. An AMD quad, where the shared
L3 is on-die, means that the cache and FSB effects are more hidden. In
the perfect scaling test, the AMD performance is 4.0 cores worth. So it
doesn't tend to choke. I have not read of any test results for Core i7,
but I presume that issue is fixed there. Since the higher end Intel processors
are more powerful than their AMD competitors, this is largely academic.
So what's not to like - if the price is good, buy it.
If you look at the pattern of the number of reviews, Q9550 2.83GHz $220 has
897 reviews, Q9650 3.0Ghz at $320 has 291 reviews, Core i7 920 2.66GHz $280 has
1476 reviews. You can either overclock a Q9550 a bit, or a Core i7 920, and
have a solid platform. For the Core i7, you need to find a cheap and solid
motherboard for it. Otherwise, the Q9550 LGA775 looks good. The Q9550S 65 watt
processor, costs too much for the power saved.
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