MSI’s New 3-Way, 4-Way SLI Bridges Have Fans

[JackNaylorPE]

I see a lot of comments here about side fans gives improvement but there is a tradeoff.

What most do not understand that if you buy something like this then chances are that you are showing it off through a side window. Where are the cases with side windows that have vents on the side window in 2016? None, and if there is a case with a side window vent then chances are that there is no dust filter which means more dust in the system specifically in the cards since they are so close together.

The Enthoo Primo provides both side fans and a window. Window is on left side, fan mounts on right.

So in a typical setup what ends up happening is that cool air comes into the front of the case, it then exhausts out of the top and back.

Or ... as in the Primo and other cases ... air flow comes in the front, sides, bottom (and top if using a radiator) and exits the rear.

A side fan in a case that does not have vents on the side window means it will just circulate the hot air inside the case. If you have a side window with a vent then chances are it is not dust proof.

All Phanteks cases have dust filers on air inlets. You are misinterpreting the purpose of the side fan:

1. The problem with air circulation between the cards in any case with adequate air changes per minute (one 140mm fan per 75 watts of heat... 50 - 100 .. for a dead silent box) is unrelated to case air flow and all about the dead air spot created between the cards which is blocked on top, bottom and rear and back side (case rear) ... 4 of 6 sides. With front card edge just an inch or so from the window, that side also limits air movement.

2. As is plainly seen in the video from above post which shows what we see when doing case air flow analysis with a fog machine, air enters bottom (poviding more than enough air for bottom card), front and side and has 0 impact on the dead air space between the cards.

3. if you look at modern case designs like the Phanteks, this issue is addressed by the provision of fan mounting screws on the back of the HD cages which allows one to create air circulation directly into the dead air space and freeing the hot air from its trapped space. Again, the bottom card operates at normal temperatures because, in any decent modern case design, is being fed with fresh outside air thru the filtered inlet on the case bottom. With 4 sides effectively 100% blocked from air flow, the fan on the back of the HD cage is way more than enough to force a) fresh cool air coming in the front of the case between the cards thru the single 100% open side of the 6 sides of that space providing cool inlet air to the top card(s) and b) to push the hot air out towards the window where, tho slightly restricted by the nearby window, it goes up and out thru case rear.

We use 6 temp sensors and a fog machine to test case air flow setup / water temps and its clear .. 58C bottom card and 68C top card goes away immediately, and tempos equalize with the addition of just one fan on back of HD cage.

I would understand if this was used with rear blower cards to get the heat out of the case but these are open air cards that will just pump hot air into the case.

Rear blower cards only exhaust part of the air out of the case.

The other problem this addresses is card droop. MSI has taken several steps recently, the first being metal reinforcing on card slots. This setup adds rigidity to the assembly and will therefore stop the front side of the card from drooping as much.