Does cache make a difference in HDD's

[Lukeor]

Hello everyone,

 

I've got to say these forums have been excellent for helping me answer questions so thanks everyone!!

 

I have a quick question, I can get hold of 2x 4tb WD Red Plus 128mb cache drives for a reasonable price (the UK market is rubbish at the moment). Does the cache size matter for a Nas/jellyfin server? 

 

I am literally going to be using them to store my own photos and videos and adding my media library to for watching via jellyfin.

 

If and when larger size drives come available at a reasonable price I will buy larger drives.

 

Cheers everyone 

[whispous]

Not really for Photos and Videos. It's nice, yes, but the drive at non-Cache speeds will read just fine for video content.

It's used for when data is being written - it will fill the Cache super fast and then the Cache wites to the spinning platters slower.

 

But writing anything big will slow to the speed of the platters anyway after a second or so.

[Lukeor]

Just now, whispous said:

Not really for Photos and Videos. It's nice, yes, but the drive at non-Cache speeds will read just fine for video content.

It's used for when data is being written - it will fill the Cache super fast and then the Cache wites to the spinning platters slower.

 

But writing anything big will slow to the speed of the platters anyway after a second or so.

Thanks for this 

[leclod]

In Switzerland it seems I can get both cache versions (128 and 256) for the same price (185usd)  

Edited April 6 by leclod

[LIGISTX]

A NAS will almost always be bottlenecked by your networking speed first. Gigabit networking is only 125 MB/s… pretty much any harddrive these days can dl sequential reads and writes sustained indefinitely at that speed. 

[Nikolithebear]

On 4/6/2026 at 1:50 AM, Lukeor said:

Hello everyone,

 

I've got to say these forums have been excellent for helping me answer questions so thanks everyone!!

 

I have a quick question, I can get hold of 2x 4tb WD Red Plus 128mb cache drives for a reasonable price (the UK market is rubbish at the moment). Does the cache size matter for a Nas/jellyfin server? 

 

I am literally going to be using them to store my own photos and videos and adding my media library to for watching via jellyfin.

 

If and when larger size drives come available at a reasonable price I will buy larger drives.

 

Cheers everyone 

As others have said, no not really.  If you're doing long file transfers of a mixed workload size it can matter.

You should be fine though, plus depending on your file system (like ZFS) you can use caching drives to help buffer that.