I had the Vantec Aeroflow on my 1800xp. It is a nice looking heatsink\fan but was louder then what I had, so I put my old heatsink and fan back on. What is on my 1800xp now is a Thermal Integration's Dr. Thermal TI-V77L heatsink with a 80mm fan that is rated at 28 dBa, 2500 rpm, and 32 cfm. A hot glue gun works wonders to mount the 80mm fan to that heatsink.
28 dBa is a lot better than 38dBa. I did give up some heatsink performance but noise is the trade off you make. With the Vantec Aeroflow, I was getting a processor temp of 38°C. With my modified Thermal Integration's Dr. Thermal TI-V77L, I was getting a processor temp of 41°C. These temps were taken after running Prime95 program for ½hour.
The Thermal Integration's Dr. Thermal TI-V77L can be bought at Newegg.com also and is priced at $18.00. I think the stock Thermal Integration's Dr. Thermal TI-V77L will have about the same cooling performance and noise, as the Aeroflow does. The Thermal Integration's Dr. Thermal TI-V77L is about half the price also.
Also, if you are thinking about using the slower TMD fan on the Aeroflow to quiet it down, the rpm's do not read out properly on the slower TMD fan (4500 rpm, 33 dBa, 30 cfm). There also has been reported some problems with the TMD fans (Vantec said they have the problems fixed) see link: <a target=new class=ftalternatingbarlinklarge href="http://www.overclockers.com/articles639/">
"YS Tech TMD Fan Problem?"</a>. The TMD fans are on sale at
nexfan.com for $4.99@
For my money, I would go with the Thermal Integration's Dr. Thermal TI-V77L and try that first. Then if to loud, change fan.