I have never heard anyone talk about this, yet the info is out there. The reason I joined this forum is to plant seeds of information that hopefully permeate through the collective consciousness.
There are a handful of games that require the N64 Expansion Pak, so generally it sounds like most N64 owners opt to leave it in their console, sometimes throwing away the Jumper Pak, which was included with the stock console. According to a[ likely incomplete list on Wikipedia](https://en.wikipedia.org/wiki/Nintendo_64_accessories#Expansion_Pak), there's 3 games that require the Expansion Pak. There is a much larger swath of games that do not require the Expansion Pak, but have *enhancements* which are enabled, often not by any software option, but solely by the insertion of the Expansion Pak. Rarely, some games have these enhancements in the options menu, most of them do not-- using the Jumper Pak is the only way to turn them off.
If these enhancements were always preferable, it would make sense to leave that red-topped, heat-sinking ram expansion Pak in your unit for 100% of your games. However, many times, it's not....
The most common *enhancement* is a hi-resolution display mode, a step up from 240p to 480i. Now, I'm not going to get into the nitty gritty of what that means. Some people may prefer 240p over 480i for N64 games, and with the vast quantity of display options from CRTs to HD upscalers, your results may vary. I think it's worth noting if you use the latter however, because typically you wanna know if you have the choice between 240p and 480i, since upscalers and hdtvs can be very finnicky with that stuff.
_Here's the catch: these hi-resolution modes almost always sacrifice **frame rate** to get a higher resolution image._
Again, this is up to personal preference, but it has been proven time and time again that frames per second are preferable to resolution, particularly for action games. On Nintendo 64 especially, I would think most people would prefer smoother animations and movement with a progressive scan over an interlaced scan with less frames.
Often times, this is not advertised at all, and I would bet that the info on Wikipedia and the internet at large is incomplete, especially when it comes to Japanese games. Therefore, it is my opinion that it is highly preferable to use the Jumper Pak at all times, unless prompted otherwise. Yes, it is highly inconvenient. Yes, only major Nintendo 64-heads would even give a crap to begin with. But there it is.
There were third party expansion paks back in the day that had a physical switch on top to swap between jumper pak and expansion pak features, but due to cheap and aging hardware, it just introduces a point of failure, and jumper pak failure mid-game can damage your console.
Recently, with the release of the[ forever pak 64](https://4layertech.com/products/forever-pak-64), a new Memory Pak that includes fram, there has been discussion of aftermarket Expansion Paks. According to some experts, this may be impossible due to the availability of such minimal RAM. If such a thing were to ever exist, I'd hope they'd have the sense to include a switch on it.
It may also be possible to modify an Expansion Pak with a switch that makes it just a simple Jumper Pak, but until this information gets out there, I don't think any expert modders have cared to devise such a thing. In theory it would be very simple, and while I have some skills, I don't trust myself enough to mod my Pak, since I couldn't afford a new one if I broke it.
Some games have increased frame rate with the expansion pak when you select low res mode in options. Some games also have higher resolution textures with the expansion pak. So, you know, maybe for some people having it in all the time is preferable. It depends on the games you are playing....