I have a doubt whether cache memory is located in the processor or at the motherboard?
Most computers have a multi-layer cache approach. The first layer - L1 cache is always located on the processor. L2 cache, the next layer up, can either be located on the CPU or on the motherboard depending on the architecture. Some systems also have a third layer of cache L3 which again could be located on either the CPU or the motherboard.
Older 486 systems, for example, had L1 in the CPU and an optional L2 on the motherboard.
Most modern systems have all the cache on the CPU.
Kind of obvious, but anyway.
Thus, the cache is always attached to the CPU itself and has nothing to do with the motherboard or even the memory.
Edit: Some people feel the need to downvote without giving comments, so I might want to add that this holds for modern systems as cache could be used on motherboards too, but isn't nowadays.