Thread: How does RAM affect a seedbox speed?

Does it limit the number of simultaneous downloads?? or speed limit?? What's the difference between like 512 mb and 1 gb ?

From my experience, it shouldn't really effect speeds. It does effect simultaneous downloads and total number of active torrents. You can avoid errors such as this with higher ram: 'Storage error: [File chunk read error: Cannot allocate memory]', I wouldn't go under 2GB of ram IMO.

Oh that's why I was getting that error :$ Thanks ! I'm not rich enough for a 2 gb seedbox unfortunately!! haha I'm just a student

Just get a Kimsufi 2G

You should be able to avoid 'Storage error: [File chunk read error: Cannot allocate memory]' with it..

It strongly effects hash recheck time and rar unpacking time

To answer the original question: actually, RAM can have a very significant impact on the performance of the torrent client (modulo configuration). Usually the main issue is Disk speed vs. connection speed. If the storage cannot cope with the traffic generated by the torrent client, there are exactly two possible scenarios:
A. the storage will overload, which in turn will cause a drop in the torrent client speed until the storage "takes a breath";
B. portions of the traffic will be queue-cached in the system memory, thus being delayed from I/O to the storage system, giving enough time to the HDDs to commit the already queued I/O operations according to the best of the HDD abilities.

There are many ways to create load on a HDD, for instance by writing/reading many small files onto/from different sectors of the disk, since HDDs are mechanical devices with their heads being their bottlenecks (double-pun not intended). This is particularly relevant when you have many different torrents in your torrent client. Note that I am not talking here about speed, but about sheer number of torrents. Ultimately, an intelligently coded torrent client will recognize any type of load on the storage system and accordingly take measures by offloading to the system memory. Whether such a torrent client exists or not is an entirely different question.

In practice, each piece from each torrent will reserve some constant amount of memory when it comes to its turn, therefore if you have really a lot of torrents being active simultaneously, it is possible to run into memory issues like the mentioned above if you don't have sufficient memory, even if your connection speed is only moderate. The size of a torrent is another important variable, because the bigger the file, the more pieces wait to be read/written.

Usually, the most common problem in practice is when the connection is too fast for the HDD, so it needs to offload to system memory. It that fails to work properly, you get all kinds of problems in terms of performance drops. One can safely estimate that the storage system has to commit the double of what the actual traffic is (just open your performance monitor and compare the disk I/O with the traffic), and this work mostly consists of partially random and scattered writing/reading. Moreover, constant traffic implies that the HDD should be able to sustain these speeds of partially random and scattered reading/writing, which is a truly difficult task in general, given the physical structure of hard drives.

Typically, modern 5400 rpm and 7200 rpm HDDs don't have issues to cope with 100-Mbit "torrenting" when one can allocate 300-400 MB of system memory to the task. Then again it also depends on the implementation, i.e. OS and torrent client.

In short, memory is required if you intend to run lots of active torrents.
If you have a very huge torrent file that you need to download. The memory is the 3rd fastest storage device next to the register, and cache. It helps to buffer these file size in the memory before writing it to the permanent storage device HDD.

In terms of indepth technicality, mvg has explained it all.

On top of what everyone has already said, it kind of depends on what you're using and how you're using it.

If you're using a linux based system and set it up to use caching, the amount of ram can have a massive effect on the performance of the system. If the system has a lot of ram to cache, it can write files to ram instead of having to directly write them to the hdd. It can then write the files to the hard drive when it has spare time. On seeding newer smaller torrents, caching can also give you a big performance boost. It can read a file and keep that file in memory so when the next access of the file comes from ram instead the hard drive.

If you're on a shared system, how the other people are using the system can also effect your performance.

When you're talking a system for torrents, the speed of the hard drive is often the hardware that limits performance.

If you're worried about performance, you're often better off looking for a server that costs a little more than the cheapest that pile as many users on to the same server as possible.

If you're using a windows based server, then ignore most of this. I have zero experience with windows servers.