Question about Intel CPUS i5 and i7

I have been a ETH miner for a little bit, mostly running a machine in the garage. I am thinking of buying 1-2 machine for zcash mining to give it a try since CPU based is cheaper. I am thinking an i5 or i7 around the same clock frequency. i5 is really fast, just doesn't have hyperthreading which is equiv of 2 threads per core potentially. Does that help the algo run faster? So what do you guys think? an i5 or i7 around the same frequency for Zcash CPU mining? Or is one of those 6 cores better?

Thanks for reading.

Get the CPU that has the highest Ghz frequency. Memory should be DDR3 1600mhz+ (or DDR4)

Hey thanks you for the input in this case AMD has really high clock frequency right? or is that a no go? is there a performance difference between DDR4 2400 or DDR4 2133? I am asking if latency is a bottle neck or ram bandwidth?

I've run tests on several machines, high frequency Intel CPUs do way better than AMD CPUs but sadly the current miner isn't optimised enough to support many cores, so the sweet spot is 1-2 cores (scaling higher than 2 has diminishing returns).

DDR3 1600 or higher is fine

You might want to look into the benchmarks https://benchmark.minezcash.com/index.php?title=Main_Page

lower Avg Time Solve is faster

Note: the benchmark tool doesn't handle running more than 1 core well but from my average blocks per day lower Avg Time Solve gives more blocks on average.

Man that is great, thanks a lot! Appreciate your help.

So based on your tests and the benchmark, I notice i7 tends to run faster. However i5 is about 35% cheaper. For example the 3.5Ghz i5 6600k is about $200 while 4Ghz i7 6700K is $300. That would make i5 a better deal in terms of dollar/hash. Factoring in the PSU/MB/RAM it would still come out to be maybe 25% per machine saving. My final question is I guess if its better to fork over the extra 100 or no?

Your best bet would be to wait as they have a private GPU miner that is ~10 times faster than a mid range 2 core CPU.

Wow that is amazing! Again thanks for your quick answers. Appreciate it.

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What about the claim of a GPU having problems mining due to memory bandwidth constraints?

THe only GPU miner owner has shown us they have 10x GPU over CPU, and states they expect this to increase. This caused Zcash to offer $30k for an open source GPU miner.

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After doing some digging around, people have been reporting that 4thread using an i7 has about 2.7x compared to 1 thread. Therefore, an i3 is actually best bang for the buck. Running 2threads at maybe 1.9x with very fast DDR4 memory sounds like the best option. You save 200 dollars difference between the i3 and i7. Surprisingly i3 can go up to 3.7-3.9Ghz.

I am the only one reporting 2.74x for 4 threads verses 1 thread, as measured by blocks gained on testnet. The CPUs are i5, 3rd generation, 1600 MHz. i7 2nd generation are about the same when using 1333 MHz DDR3, at twice the electrical cost (i7-2600's). Memory management on the CPU might make a substantial difference. But you've got a good theory. The newest xeons at 2.5ish GHz are a lot slower than my 3.2ish old i5's.

10 times faster = huge chinese gpu farms everywhere. I wish zcash would requires 2gb per cpu core or more, all modern pc comes with 16gb ram

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Hyperthreading: All i5 processors are Quad Core and hence have 4 physical cores serving 4 threads. All i7 processors also are Quad Core but they are equipped with Hyperthreading technology which enables each core to serve 2 threads, hence the OS sees it as an Octa Core Processor rather than a Quad Core Processor.

Cache Size: RAM minimizes the use of Hard Drive similarly Cache minimizes the use of RAM. The more the Cache size, the more data can be accessed quickly. Most i5 processors(if not all) have a cache size of around 4MB (3,4,5 or even 6MB in some of them) but almost all i7 Processors have 8MB cache, which is significantly more, thereby allowing more amount of data to be accessed quickly.