[Windows Mobile] indagroove:
It seems to me that there are two ways to view the question posed by the OP. One is the question of whether cooking in applications slows down the rom vs installing the same applications via cab. The other is whether cooking in more applications slows down the rom assuming that you never cab install the application post flash.

In regards to the question of cooking in vs cab install, I'm not sure why you would think that cab installing would somehow permanently take up ram space, unless by "ram" you're referring to storage space. But consider the fact that with many applications you have quite a bit of initflashfiles.dat code to go along with it. Take one of the most commonly cooked in applications in roms today, Opera Mobile -- here's what my initflashfiles.dat for Opera looks like these days:

Directory("\Windows"):-Directory("Opera9")
Directory("\Windows\Opera9"):-Directory("profile")
Directory("\Windows\Opera9\profile"):-Directory("help")
Directory("\Windows\Opera9\profile\help"):-Directory("imgcss")
Directory("\Windows\Opera9\profile"):-Directory("images")
Directory("\Windows\Opera9\profile"):-Directory("jsplugins")
Directory("\Windows\Opera9\profile"):-Directory("locale")
Directory("\Windows\Opera9\profile"):-Directory("Settings")
Directory("\Windows\Opera9\profile\Settings"):-Directory("Imgs")
Directory("\Windows\Opera9\profile"):-Directory("skin")
Directory("\Windows\Opera9\profile"):-Directory("styles")
Directory("\Windows\Opera9\profile\styles"):-Directory("images")
Directory("\Windows\Opera9\profile\styles"):-Directory("user")

Directory("\Windows"):-File("Opera9.exe","\Windows\Opera9.exe")
Directory("\Windows"):-File("OperaL.exe","\Windows\OperaL.exe")
Directory("\Windows\Opera9"):-File("Opera_loading_POR_16bit_default.png","\Windows\Opera_loading_POR_16bit_default.png")
Directory("\Windows\Opera9"):-File("Opera_loading_Landscape_16bit_default.png","\Windows\Opera_loading_Landscape_16bit_default.png")
Directory("\Windows\Opera9"):-File("line.png","\Windows\line.png")
Directory("\Windows"):-File("HTC_opera.png","\Windows\HTC_opera.png")

Directory("\Windows\Opera9\profile"):-File("axobjects.ini","\Windows\axobjects.ini")
Directory("\Windows\Opera9\profile"):-File("encoding.bin","\Windows\encoding.bin")
Directory("\Windows\Opera9\profile"):-File("html40_entities.dtd","\Windows\html40_entities.dtd")
Directory("\Windows\Opera9\profile"):-File("input.ini","\Windows\input.ini")
Directory("\Windows\Opera9\profile"):-File("svg_mono.dat","\Windows\svg_mono.dat")
Directory("\Windows\Opera9\profile"):-File("svg_serif.dat","\Windows\svg_serif.dat")
Directory("\Windows\Opera9\profile"):-File("svg_ss.dat","\Windows\svg_ss.dat")
Directory("\Windows\Opera9\profile"):-File("svg-mo.dat","\Windows\svg-mo.dat")
Directory("\Windows\Opera9\profile"):-File("svg-mobd.dat","\Windows\svg-mobd.dat")
Directory("\Windows\Opera9\profile"):-File("svg-moit.dat","\Windows\svg-moit.dat")
Directory("\Windows\Opera9\profile"):-File("svg-sa.dat","\Windows\svg-sa.dat")
Directory("\Windows\Opera9\profile"):-File("svg-sabd.dat","\Windows\svg-sabd.dat")
Directory("\Windows\Opera9\profile"):-File("svg-se.dat","\Windows\svg-se.dat")
Directory("\Windows\Opera9\profile"):-File("svg-sebd.dat","\Windows\svg-sebd.dat")
Directory("\Windows\Opera9\profile"):-File("svg-ssit.dat","\Windows\svg-ssit.dat")
Directory("\Windows\Opera9\profile"):-File("browser.js","\Windows\browser.js")
Directory("\Windows\Opera9\profile"):-File("wml1_entities.dtd","\Windows\wml1_entities.dtd")
Directory("\Windows\Opera9\profile"):-File("xmlentities.ini","\Windows\xmlentities.ini")
Directory("\Windows\Opera9\profile"):-File("user.js","\Windows\user.js")

Directory("\Windows\Opera9\profile\help\imgcss"):-File("bullet.gif","\Windows\bullet.gif")
Directory("\Windows\Opera9\profile\help\imgcss"):-File("help.css","\Windows\help.css")
Directory("\Windows\Opera9\profile\help\imgcss"):-File("logo.png","\Windows\logo.png")
Directory("\Windows\Opera9\profile\help\imgcss"):-File("top_pattern.png","\Windows\top_pattern.png")

Directory("\Windows\Opera9\profile\images"):-File("arrow.png","\Windows\arrow.png")
Directory("\Windows\Opera9\profile\images"):-File("beam.png","\Windows\beam.png")
Directory("\Windows\Opera9\profile\images"):-File("blank.gif","\Windows\blank.gif")
Directory("\Windows\Opera9\profile\images"):-File("cross.png","\Windows\cross.png")
Directory("\Windows\Opera9\profile\images"):-File("delete.png","\Windows\delete.png")
Directory("\Windows\Opera9\profile\images"):-File("drive.gif","\Windows\drive.gif")
Directory("\Windows\Opera9\profile\images"):-File("error.png","\Windows\error.png")
Directory("\Windows\Opera9\profile\images"):-File("file.gif","\Windows\file.gif")
Directory("\Windows\Opera9\profile\images"):-File("folder.gif","\Windows\folder.gif")
Directory("\Windows\Opera9\profile\images"):-File("forward.png","\Windows\forward.png")
Directory("\Windows\Opera9\profile\images"):-File("hand.png","\Windows\hand.png")
Directory("\Windows\Opera9\profile\images"):-File("info.png","\Windows\info.png")
Directory("\Windows\Opera9\profile\images"):-File("link.gif","\Windows\link.gif")
Directory("\Windows\Opera9\profile\images"):-File("move.png","\Windows\move.png")
Directory("\Windows\Opera9\profile\images"):-File("oom.png","\Windows\oom.png")
Directory("\Windows\Opera9\profile\images"):-File("open.png","\Windows\open.png")
Directory("\Windows\Opera9\profile\images"):-File("opwidget.ico","\Windows\opwidget.ico")
Directory("\Windows\Opera9\profile\images"):-File("question.png","\Windows\question.png")
Directory("\Windows\Opera9\profile\images"):-File("reload.png","\Windows\reload.png")
Directory("\Windows\Opera9\profile\images"):-File("stop.png","\Windows\stop.png")
Directory("\Windows\Opera9\profile\images"):-File("trash.png","\Windows\trash.png")
Directory("\Windows\Opera9\profile\images"):-File("wait.png","\Windows\wait.png")
Directory("\Windows\Opera9\profile\images"):-File("warning.png","\Windows\warning.png")

Directory("\Windows\Opera9\profile\locale"):-File("search.ini","\Windows\search.ini")

Directory("\Windows\Opera9\profile\Settings"):-File("settings.html","\Windows\settings.html")

Directory("\Windows\Opera9\profile\Settings\Imgs"):-File("bar_closed.png","\Windows\bar_closed.png")
Directory("\Windows\Opera9\profile\Settings\Imgs"):-File("bar_open.png","\Windows\bar_open.png")
Directory("\Windows\Opera9\profile\Settings\Imgs"):-File("list_btn.png","\Windows\list_btn.png")
Directory("\Windows\Opera9\profile\Settings\Imgs"):-File("txt_fld.png","\Windows\txt_fld.png")

Directory("\Windows\Opera9\profile\skin"):-File("standard_skin.zip","\Windows\standard_skin.zip")

Directory("\Windows\Opera9\profile\styles"):-File("about.css","\Windows\about.css")
Directory("\Windows\Opera9\profile\styles"):-File("cache.css","\Windows\cache.css")
Directory("\Windows\Opera9\profile\styles"):-File("certinfo.css","\Windows\certinfo.css")
Directory("\Windows\Opera9\profile\styles"):-File("config.css","\Windows\config.css")
Directory("\Windows\Opera9\profile\styles"):-File("dir.css","\Windows\dir.css")
Directory("\Windows\Opera9\profile\styles"):-File("drives.css","\Windows\drives.css")
Directory("\Windows\Opera9\profile\styles"):-File("error.css","\Windows\error.css")
Directory("\Windows\Opera9\profile\styles"):-File("history.css","\Windows\history.css")
Directory("\Windows\Opera9\profile\styles"):-File("info.css","\Windows\info.css")
Directory("\Windows\Opera9\profile\styles"):-File("mime.css","\Windows\mime.css")
Directory("\Windows\Opera9\profile\styles"):-File("plugins.css","\Windows\plugins.css")
Directory("\Windows\Opera9\profile\styles"):-File("wml.css","\Windows\wml.css")

Directory("\Windows\Opera9\profile\styles\images"):-File("88c.png","\Windows\88c.png")
Directory("\Windows\Opera9\profile\styles\images"):-File("bar.png","\Windows\bar.png")
Directory("\Windows\Opera9\profile\styles\images"):-File("center.png","\Windows\center.png")
Directory("\Windows\Opera9\profile\styles\images"):-File("folder.gif","\Windows\folder.gif")
Directory("\Windows\Opera9\profile\styles\images"):-File("opera.png","\Windows\opera.png")
Directory("\Windows\Opera9\profile\styles\images"):-File("root.png","\Windows\root.png")
Directory("\Windows\Opera9\profile\styles\images"):-File("top.png","\Windows\top.png")

Directory("\Windows\Opera9\profile\styles\user"):-File("accessibility.css","\Windows\accessibility.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("contrastbw.css","\Windows\contrastbw.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("contrastwb.css","\Windows\contrastwb.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("debugwithoutline.css","\Windows\debugwithoutline.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("disabletables.css","\Windows\disabletables.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("hidecertainsizes.css","\Windows\hidecertainsizes.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("hidenonlinkimages.css","\Windows\hidenonlinkimages.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("imageandlinkonly.css","\Windows\imageandlinkonly.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("nostalgia.css","\Windows\nostalgia.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("showstructure.css","\Windows\showstructure.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("textonly.css","\Windows\textonly.css")
Directory("\Windows\Opera9\profile\styles\user"):-File("userstyle.ini","\Windows\userstyle.ini")

Directory("\Windows\Start Menu\Programs\Internet\"):-File("Opera Browser.lnk","\Windows\Opera Browser.lnk")

So, what does this mean? It means that for every line of code, you have double the files that are needed to actually run this application. What's going on here is that every files gets put in the windows folder and is also copied to the designation specified in the code, which is where it is actually used. There files are in most cases not ever used at all in the windows folder, but there are there nonetheless. I guess a really slick chef would write a provxml that would delete all the duplicates in windows for a really slim rom (that would be a neat trick).

When you cab install these same applications, the files are installed directly the the designated folders, and you don't get duplicate files put in the windows folder like when you cook them in.

I know, you're gonna say "so ok maybe you have some extra files, who cares?" Well, a few extra files are cool but they really do start to add up over time. Take the Manila packages for example. I think that most Manila 2.5 these days is typically over 3000 files. When your device has to run an app that resides in the windows folder, it has to search through all the files that are in the windows folder to find the needed file(s). The more files in the windows folder, the longer it takes to find and load the desired file = fact. How much longer does it take is the real question. Is it something that we can actually perceive, or can it only be found through benchmarking. The point can easily be proven/disproven by any competent chef by doing a Manila build, then disable manila and benchmark. Next build an identical rom without manila and benchmark that rom. I can pretty much guarantee that the rom without manila will out perform the rom that includes manila, even with manila disabled.

The other thing to consider with cab installs vs cooking apps, is that many apps have dll and exe files as modules natively, and when these modules are cooked in, they are loaded into the xip, which obviously occupies xip space and can potentially eat up ram. When you cab install apps, the modules are converted to files in the cab installer, and do not occupy the same xip space. Typically more space in the xip = faster processing and more available ram.