Fan noise, RAM upgrades, and assorted stuff
Originally posted by airmac
So, how loud is iMac?
Fan Noise
I can't comment on this model, but iMacs use a chimney design with intake on the rounded bottom (very hard to block these), hot air out of the top, and a single large fan situated at the top of the dome to pull the air. The parts are stacked one on top of each other so the air visits each part before coming out the top. One part (the hard drive?) is wrapped in a malleable metal perhpas to act as a heat sink (but I can't be sure, perhaps its for interference reasons). I think the design is pretty similar to the old G4 Cube but with the addition of the fan (on the + side this means it can take a faster hard drive, be cheaper, etc.).
In general, I think it is the more efficient than anything in the PC world. For instance, the favorite SFF PC is the Shuttle which uses a heat pipe to get around the horrible geometry issues so it can cut down the number of fans to one (two if you have a machine whose northbridge neads a fan, three if you add an AGP card). The intakes are on the lower side and are very easy to block (I've seen one SFF PC design that actually blocks the intakes with a set of speakers). Airflow seems very haphazard, especially with the addition of an AGP card. There are some serious heat issues reported with such things. (In their defense, I own a number of them and have not personally had any of them fail due to heat--then again I don't install any high end AGP cards in them nor do I overclock them).
The subjective noise level of the iMac is low. My test is that the hard drive disk whirr bothers me in the case of the iMac (I have replaced the hard drive with an IBM/Hitachi so YMMV), but is not especially noticeable above the fan noise in any Shuttle I've owned. G4 processors much less power than a Pentium 4 (even these overclocked MPC 7455s in the new iMac)--the MPC7455 uses 15 watts @ 1Ghz, while the P4 uses over 100 if you're crazy enough to use a 3.2Ghz P4.
BTW. Noise level is related to fan noise which is related to airflow design, quality and number of fans, and the amount of heat that needs to be dissipated. Heat dissipation is directly proportional to power usage.
If I had to guess as to why the iMac (and the G4 PowerMac) isn't available at 1.4Ghz, I'd say that there are probably yield issues at turning out enough quantities, not a heat issue.
It's a real good design, IMO, but I think the iMac might have to be redesigned when consumer graphics chipsets will start requiring fans.
RAM Upgrades
As mentioned the iMac has two slots. One is a user-serviceable SO-DIMM slot (this means notebook RAM so it will cost you more). It is very easy to upgrade and instructions are available on Apple's website as well as the included manual (I think). Basically you unscrew the bottom plate and you can add the Airport Extreme (and I guess Bluetooth also) and the SO-DIMM.
The other DIMM is on the motherboard which is not an easy thing at all to upgrade. While I was upgrading the hard drive, I changed out the DIMM on my old iMac, but everyone who saw my disassembly and thought it was nuts--I'm sure it must void the warrantee. I don't recommend doing so, though it will give you a healthy respect for Apple design and build quality.
Headless Macs
Yeah, count me in as someone who wishes they came out with a headless Mac for cheaper than an eMac. Not that that changes anything, I have different needs than most (I wouldn't mind some cheap web servers running Mac OS X client) and probably represent a minority that would be outweighed by the number of lost sales of eMacs and PowerMacs (as well as the tech support headache of external monitors, resolutions, antialiasing settings, and DVI vs. VGA).
Just goes to show that you can't please everyone.
G5 iMac
As has already been mentioned, I'm with the crowd who think that there won't be a G5 iMac anytime soon: the line has just been refreshed; they can always refresh again with an L3 cache or an MPC 7547 (which will probably go in the new Powerbooks); there are probably more G4 speed bumps from Motorola ahead as the 7455 isn't even at 130nm (of course this means a lot of frustrating Motorola delays
😉; and the G5 represents a singular distinction between pro/consumer desktop lines. Heck, Apple is still plugging the 2x1.25Ghz G4 PowerMac.
I hope this helps,
terry
