Post
Topic
Board Altcoin Discussion
Re: CPU friendly Altcoin in development
by
DeathAndTaxes
on 31/07/2013, 02:47:30 UTC
From what I heard scrypt miners use the L3 cache of the GPU/CPU, not the RAM. Could it be possible that if enough memory has to be used the performance difference between GPUs and CPUs disappears?
Also, an algo favoring lots of RAM could be interesting, if one exists.

exactly!
I made somewhere point on this forum that there should be coin that uses for example 16GB of RAM so that we cant implement this in gpu ?
Or more likely cant do ASICs hmmmm or meaby not Cheesy

Anyway coin that would require at least 8GB memory would be nice alternative Smiley
Based od AES ? (i7 have hardware acceleration) ?

You wouldn't need 6GB.  The latency on main memory for a GPU is horribly bad so bad that any process which needs random access to GPU main memory will be annihilated by a CPU in terms of performance.  GPU memory is designed to stream textures and as such it couples massive bandwidth with extreme latency.  Scrypt was designed to fill the L3 cache of a CPU.  The developers of alt-coins had to intentionally lower the memory requirements by 99% to make GPU competitive.  Yes Litecoin and clones use about 128KB of cache.  The MINIMUM memory requirement for Scrypt is 12MB.  It doesn't take 16GB.  Try it out yourself or check out various hacking forums the OpenCL performance for Scrypt (2^14, 8, 1) is beyond pathetic.  A cheap CPU will run circles around it.  

Of course this makes it optimal for botnets so maybe a higher memory requirement (say 4GB/8GB) may be an idea so that it requires a relatively high end computer.  Scrypt is configurable you can make the scratchpad as large as you want (even up to TB of space required). It would be trivial for enthusiast to add more memory/disk but I imagine the average botnet node is a relatively weak/older system.  The % which have 4/8GB or more of main memory are probably small.  One could even design the algorithm to become more memory hard over time (i.e. double memory requirement every 2 block years).