When I opened up my 871W, I saw the on board 128MB memory chips are actually made by Winbond. In history the quality of Winbond chips in general is not as good as Micron chips. But they are cheaper than Micron in average. I also added a half height Micron chips PC133 128MB module to my 871W, $25.00, it was pulled from an old PCs.
I ordered Crucial memory modules many times in the past, Crucial is no longer a Micron chip only company, they are selling modules with other brands on it.
Cisco documents show you how to open up routers and install memory on your own, that means they are not making it tough on voiding the warranty on self-installation activities. I am sure Cisco has calculated the potential customer support costs and expenses caused by these users activities, otherwise, they would never make those documents public.
Cisco never post detailed performance spec on their compact flash, whether it is 2x, 4x ... 120x etc. The only thing I see is the outrageous high prices. It is deceptive, it makes us think their "branded" memory is better than other brands.
I just received my SilenX 40x40x20mm fan and Transcend 128MB 80x CF, there may be other faster 128MB CF out there, but I can't find them. 80x should be good enough. There is a cheap $5 PNY brand 128MB available www.compusa.com but PNY doesn't post the spec, this Transcend 128MB 80x is around $12 including shipping. The lowest price in history was $5.00 with free shipping. Since logs will be saved to CF on 1811, I better get a fast CF for better performance.
The production of CF sizes below 512MB are becoming less and less, 2GB/4GB CF are the current main production lines. You even see 256MB CF/SD free after rebate, 512MB is just around $15. I'd suggest you to get fast 128MB CF or 256MB CF for your routers quick, don't wait any longer, once these fast and cheap CFs are gone, you will need to buy those $500 Cisco brand CFs.
I am going to install the fan and CF and let you know the result.