I thought I'd try to relax and do something fun whilst cleaning up my computer room this weekend. I decided that I'd test a few of the "vintage" waterblocks for SocketA that I have lying around. Why not, right? I thought that it'd be fun to see how much performance has improved since roughly the time I joined Procooling. I don't have my old Maze 2 any more

so I couldn't run my first waterblock. But I did have a Danger Den Maze 3 (copper top), a Swiftech MCW462-UH (with 1/2" barbs), and one of the original Spir@ls from fixxxitt. So I figured I'd run quick tests on them and just show you guys how performance has changed over the years.
By quick tests I mean that I did one "test mount" to make sure I was making good contact between bp and CPU and then mounted the block once and ran a flow test with 30 minutes between points. CPU speed and vcore as normal (175 fsb x 12.5multi and 1.825V).
All of the wbs are "center inlet" designs, and the Maze3 and Spir@l are both fairly free-flowing spiral channels that lead to an exit. The Swiftech has an open deisgn with a number of divots drilled into the copper baseplate over the die area. Compared to the blocks we use today, these blocks have much less surface area, less resistance, and rely fairly heavily on pump power to get the job done.
It seems pretty clear that the Spir@l was more about hype and attractiveness than it was about true performance. I'm sure many of you remember them being
highly sought after. It's also interesting that none of these blocks have good performance at flow rates below 1GPM. These were among the first blocks produced in the "switch to 1/2" hose and heatercores and go for high flow" period as I recall.
Swiftech and Danger Den are arguably the two most important wb manufacturers in the US, and both have been providing commercial wbs for many years. We can take a look at how their waterblocks have evolved over time and perhaps get some insight into how their design process works. Let's start with Danger Den:
It's interesting to see that all the Danger Den blocks have always had more or less the same shape to their dT vs flow curves. The Maze4 is actually capable of higher than 2.5 GPM flow rates on my test loop; regrettably I didn't test up that high when I ran it the first time and I no longer have the block (BrianS does). We can see a pretty steady improvement in performance as Danger Den released new waterblocks. The exception (on this graph) is the TDX, but in fact it's a good bit less restrictive than the RBX so performance is very close in real world use. Overall though we can see that Danger Den has pretty consistently been designing blocks that benefit substantially from increasing flow rates. Danger Den's choice of components for their kits makes reasonable sense given the blocks: heatercores and 1/2" ID tubing. They used to sell their kits with Eheim pumps, and brought the Laing D4 pumps to US water coolers.
Now let's look at the Swiftech waterblocks:
What we see here is a fundamental change in design strategy from the earlier blocks (MCW462-UH) to the newer blocks (MCW5000 and 6000). The MCW462-UH was released primarily to appease all the DIYers with 1/2" loops. It actually performs considerably worse than the 3/8" MCW462-U block Swiftech used in their kits. BillA demonstrated a performance mod for the MCW462-UH in
an article for Overclockers BTW. The MCW462 series blocks obviously relied heavily on flow rates to produce turbulence over the die area. Unlike the Danger Den blocks, newer Swiftech blocks have decidedly different performance curves. The MCW5000 and 6000 are designed to improve cooling performance at lower flow rates compared to the older Swiftech blocks. They have much greater surface area (pins) and (I would guess) a somewhat thicker baseplate. These changes lead to a much flatter performance curve and better performance at low flow rates for the MCW5000-A. This makes good sense because Swiftech was bundling their MCW5000 series waterblocks with 3/8" tubing, black ice micro radiators(s), GPU blocks, and a fairly low pressure pump. Swiftech then brought a much higher pressure capacity pump to the community (the MCP600) and shortly afterwards released a new waterblock designed to make good use of higher flow/pressure loops. That block is the MCW6000, their current offering. THIS block's performance curve does have essentially the same shape as the MCW5000 (only shifted down considerably).
Anyway that's my little personal indulgence and trip down memory lane. I am eager to see how the next blocks from Swiftech and Danger Den will look and perform.