Sapphire HD3870 512MB TOXIC Edition Review

Under the Heatsink

Please remember that removing the heatsink on this card will void your warranty.


After unscrewing the seven screws holding it down and then carefully sliding it off, we are finally able to see what lies below the Vapor-X cooler. Even though we will be taking a look at the Vapor-X in detail a bit later, upon first glance it looks to be a standard heatsink with a copper base plate and thermal pads for the ram modules. There is a perfect amount of thermal compound applied to the core and while we are talking about the core, we may as well mention that even though the PCB is custom, the heatsink mounting holes are in the exact some position as those on a reference card.


After the thermal compound is cleaned off, we get a full view of the RV670XT core along with the Samsung GDDR4 memory modules which are 64MB x 8 pattern for a total of 512MB of ram. These Samsung K4U52324QE-BC080 modules are rated at 1200Mhz (2400Mhz DDR) so there should be a bit of overclocking headroom left in them since they are spec’d at 1150Mhz on this card. You can find the full spec sheet here: http://www.samsung.com/global/system...24qe_rev12.pdf

A Closer Look at the Vapor-X Heatsink

Since we had a beautiful looking single-slot heatsink sitting in front of us, we quickly succumbed to the temptation to take it apart too see how it ticks. While on the next page we will look at the technology behind the Vapor Chamber cooling concept, here we take a quick look beyond those pretty presentation slides at the nitty gritty details of the actual heatsink. Upon first glance it looks like a run-of-the-mill, single-slot heatsink the likes of which we have seen a million times before. However, there is much more to it than what first meets the eye.


After popping open the hood we are greeted with a high density aluminum fin assembly which is used to disperse the heat generated through the copper contact plate. Interestingly, the entire vapor chamber is enclosed in copper instead of this highly valuable material (now at an all time high on commodity markets) being only used for the small area of the heatsink that actually comes in contact with the core. Since copper is such a good heat conductor, it makes sense that Sapphire would use it almost exclusively for the entire underside of this heatsink.

This is all capped off with a 13-bladed, 60mm low profile fan which is positioned to push as much cool air as possible over the fin assembly.


With these densely packed aluminum fins, it looks like the fan will have to spin for all its worth in order to vacate the heat as quickly as possible. As we will see later, this leads to increased noise levels but it is a tradeoff you have to be prepared to pay for single slot cooling.

The vapor chamber is capped off with what looks like a small copper knob and while this may look odd, it seals the whole vapor chamber within its copper enclosure.


Here we have finally come to some very lurid and disappointing shots of this heatsink and let me tell you: it ain’t pretty. Copper corrosion is the name of the game here where it looks like the glue which holds the metal support plate in place has begun eating away at the copper itself. This it is THE only graphics card where we have seen a situation like this and since this cooler is supposed to be the Toxic’s crowning glory it boggles the mind why quality was allowed to slip like this. However, it should be noted that Sapphire is aware of this problem and they will be rectifying it on future models that use this heatsink design.