I'm trying for the life of me to find the difference between between a Toshiba Satellite 1800 and a 1800-S100. Am I just looking for something that isn't there? Is the 1800 just a series and the S100 a model in the series? I am asking because I'm looking to upgrade the RAM on my sister's laptop, and depending on whether I input 1800 or 1800-S100 in the "memory finder" apps on memory sites I get different results for what is compatible (either PC100 or PC133 SDRAM, depending on what I put in). As far as I can tell, her model number is PS181C-00CET, and these are the sites that are confusing me,leading me to think the two computers are same bloody thing: http://www.toshiba.ca/web/specifications.grp?lg=en§ion=1&group=223&product=4∂=4 http://209.167.114.38/ISG/pastproducts/html/satellite/satellite_1800-S100_spec.html Ultimately, which memory should I buy (100 or 133) and does it matter? I don't know what is already in the PC, and right now it's overseas so I unfortunately can't check.

The S100 indicates the memory is PC100 SDRAM. This is slower memory than the PC133, tho the difference isn't that great, compared with more modern memory. It is possible that you could use either type. Here is what I would do, tho: Go to Crucial.com and use their memory configurator. Enter the model number, as shown above, for the laptop. It will list all suitable memory types that you can use. You don't have to buy it from them, but you could use their model number to search for it. That's how I found the memory for my desktop, on eBay. Good luck. I hope this helps. :) Bob

Hey Bob, Thanks for the response! One thing though - I tried Crucial and they dont list any memory for Satellite 1800 series. :( I tried 4allmemory.com and that's where I got the conflicting info between the two computer models: SDRAM PC100 and PC133 for two seemingly identical Toshibas, and hence my problem not knowing which to get.

Hi. I have a satellite 5005 and as you said Toshiba refers to the 5000 series to include all models in the series. I am not familiar with the model you quote but usually PC100 and 133 are interchangable. If you have a 133 system you can use 100 but then the memory will run at the slower speed including any 133 memory that may be installed.Likewise if the system is 100 it will run with 133 memory but at the slower speed. If you are not sure of the existing memory in the system go with the 133. If it's a 133 system you are getting the benefit of the 133 and if it's 100 it will rum anyway and the cost is little different. Cheers Stewart Bit of a wit....half to be precise.

Thanks guys. It appears the 1800 is indeed just a series, and the 1800-S100 is the right sub-series/model. Toshiba is retarded, seems they have two names for every laptop. Time to buy another Dell.