Axe said:
Thank you Paul. I'm amazed at how much you know on the subject. I see
many well written posts here. Sorry about the missing reference. You
actually found the thread I was referring to. Here it is again
http://groups.google.ca/group/alt.comp.hardware/browse_frm/thread/7eefc4b3cd1d5c9a/37136fd9562c94d3.
A couple of follow up questions. Can I purchase a better fan? I'd
rather spend a few extra bucks than fry my system because of the
upgrade. Also, will the addition of a card like the 8800GT allow me
to play games like Crysis, for example, on the highest resolution
settings? I'm trying to understand what kind of performance to
expect. Also, do I need to do something to disable the current built
in graphics card or do I just select the card I want to use in
settings (I'm using Vista)? By the way, as I mentioned I have 4 gigs
of memory in this computer. Does having the extra gig really do
anything for me?
Thank you
I'm having a bit of trouble finding a picture of the inside of
your computer. It is hard to tell what options are available for
modifying the cooling.
*******
Fans come in a number of standard sizes. 60mm, 80mm, 92mm, 120mm,
would be some examples of 12V DC brushless fans. The fan thickness
might be 25mm (and I have one in my current case that is 37.5mm
thick). As well as all those sizes, fans come in low, medium, high,
and ultra. Those span a range of CFM (cubic feet per minute) and
noise.
If you have a choice, you'd generally try to avoid a smaller fan.
The smaller they are, the faster they spin. (I have a 40mm fan
that is rated at around 8000RPM or so. Larger fans may be in
around 1200RPM for some of them.) The 8000 RPM fan whines pretty
bad, and you wouldn't want to sit next to it.
The low and medium fans would be "quiet", with the medium competing
with other noise sources in your computer. The high and ultra can
definitely be heard. I guess the fan I've got, would be close to
an ultra, but I don't feed it full voltage (it is too loud that way).
I use a voltage reducer, and it runs closer to a high as a result.
Your case will have a fixed size area for a fan, with standard
hole spacing for a standard fan. If you were going to replace the
fan, you'd want something with more CFM. If you replaced the fan
with something quieter than your current fan, chances are it would
not cool as well.
Since I don't have a good picture of the inside of the case, I
don't know if the processor has a plastic shroud over it, and
the back fan on the case is part of that assembly. Of whether
you have a more conventional retail AMD cooler on the processor,
and the fan is just a fan, affixed to the back of the case. If
the latter, you may be able to replace it.
In addition to all these details, it is possible your rear fan is
thermally controlled. As the case temp rises, the fan may
automatically speed up to compensate. In which case, if the
fan is not running at full speed, it may do a good job of
keeping the temperature down.
The fan I'm currently using, is more of an accident than a
design. I was at the one good electronics store in town, looking
at their fan collection. I spotted a fan with an aluminum frame,
instead of the usual plastic. The fan was an impulse buy, and later
was added to my current computer.
When I first installed it, it didn't seem too effective. With the
computer running, I could take the side off the case, and I'd
notice that the fan would slow down its RPMs. That is the same
effect you get when you put your hand over the end of a vacuum
cleaner hose. The symptoms mean, my case doesn't have enough
air intake vents. I removed a plastic piece on the front of my
case, to make more room for airflow. That made it easier for
the fan on the back, to pull air through the ocmputer case.
Fixing cooling is more than just changing the fan, it also includes
intake vent planning.
The airflow has to be carefully planned as well. Looking at the
manual for your computer, they show a vent which looks like it is
pretty close to where the back fan is exhausting. If you put
an intake vent, close to the fan, the resulting air flow doesn't
service the entire case. The best way to route the air, is have
it enter the computer via the front of the case, and leave by the
back. The cooling effect then helps components all along the inside
of the computer case. If vents are added too close to the exhaust
fan, then other parts of the case may not receive any cooling.
If the computer had just one exhaust fan, you could use a
formula like this. With your new video card, maybe the power
might be 250W. For a well cooled computer case, you want a
delta_T of about 10F (=7C). The reason for cooling like that,
is to keep the case air temperature down. If the room is 25C,
then the case would be 32C, and the CPU and video card coolers
are using 32C air to keep them cool.
CFM = 3.16 x Watts / Delta_T_degrees_F [ Formula for case cooling ]
Solving for CFM, we get 3.16 * 250 / 10 = 79CFM
If we have a look here, there are some 120mm fans that deliver
close to that number. Alternates are an 80mm with 39CFM, a 92mm with
50CFM. Using a less capable fan, means the inside of the computer case
gets warmer (work the above equation, to figure out how much
warmer). (I'm using this site, because Newegg is down right now.)
http://www.circuittest.com/English/Content/Divisions/Div_37_120.asp
Probably, judging by the sound, the current fan is not producing near
that flow rate. One way to think of the problem, is your new graphics
card increases heat by 30 to 40%, so you need 30 to 40% more fan.
I hope that gives you some idea.
*******
Answers to your other questions:
1) When the new graphics card comes, remove the old graphics driver
(but keep the installer around, in case you'll need it again).
Shut down. Install the new graphics card. Install the new graphics
driver. The built-in graphics should be disabled by the BIOS.
(There are a limited number of motherboards, where the built-in
continues to run, and then you could try disabling in Device Manager
if you want. Alternately, if the BIOS has a shared memory setting, on
some, setting it to zero may give it a hint to go away.)
2) Nothing runs Crysis well
But certainly it'll be miles better
than the built-in. On games, usually there are well known features
(which don't necessarily improve game play), that are expensive to
support performance wise, and turning those off is enough to make
the game playable. You can still keep textures high, use a bit of
AA if you want and so on.
3) The new graphics card will have memory on it. The memory on the card,
uses address space. Like street addresses, all your hardware needs a
unique address. If you are using a 32 bit OS, you may find that the
free system memory drops to 3GB, even though you have 4GB installed.
You should notice a drop of another 256MB or 512MB or so, from whatever
figure it is currently showing. (2GB should be enough for a lot of games.)
The 32bit OS/address space issue gets even worse, if you had an SLI system.
Some users with 512MB cards in SLI, find that free system memory is listed
as 2.5GB, even though they have 4GB installed. A 64 bit OS and memory
remapping, can help, but probably won't be needed right now.
There are some comments here on Crysis on an 8800GT. Staying above
30FPS is what you're after.
http://www.crysis-online.com/forum/index.php?topic=20010.msg294669
HTH,
Paul
