OT: What features do you look for in an x86 processor?

[Rod Pemberton]

Hey guys, I'm curious, what features do you look for in an x86
processor?

How would you rank the following in terms of importance for a
processor's performance?

clock speed
cache size
unlocked cores
number of cores

I would probably rank them as listed above.

For a long time now, I've been really happy with an unlocked processor.
The unlocked nature of the processor means it doesn't usually grind
away at a task for a long time, but it finishes in a quick blip, even
though it's only a dual-core. In other words, it seems that processor
speed - both raw clock speed and extra speed from the unlocked cores -
is far more important than having more cores. From earlier processors,
it seemed that a bigger cache was the next biggest improvement after
clock speed. But, of course, this processor is a decade or so old now.
I'm sure you guys have moved on to newer hardware. What are your
thoughts on this? Has much changed in regards to this over the past
decade?


--

[Scott Lurndal]

Post by Rod Pemberton
Hey guys, I'm curious, what features do you look for in an x86
processor?
How would you rank the following in terms of importance for a
processor's performance?
clock speed
cache size
unlocked cores
number of cores
I would probably rank them as listed above.

It's entirely dependent up on the desired workload.

Clock speed is a curious thing, most processors today
have multiple clocks (a base board clock, then clocks
for ethernet PHYs, various I/O controllers (e.g. SPI, MMC),
and the cores which are derived from the base board clock
via programmable multipliers which can be independenly
and dynamically adjusted in real-time).

I'd be looking to ensure the ISA supports the needs
of the desired workload (i.e. are SIMD instructions
required? 128-bit? 256-bit? 512-bit SIMD? Does the
cpu support the non-deterministic random number
generation instructions - important for crypto workloads?)

DDR speeds are also significant - does the memory controller
in the chip support DDR4? DDR5? How many transactions/sec?

Is the workload single threaded? Higher clock speeds
or highly optimized cores may be best. Otherwise, how
parallelizable the workload is defines the requisite
core count.

Bus width - does the application require more than 2^40,
2^44, 2^48 or 2^52 bits of address space for memory and/or
add-in PCI express devices?

Do the memory controllers support ECC? A system without ECC
is useless for most real-world workloads.

[wolfgang kern]

Post by Rod Pemberton
Hey guys, I'm curious, what features do you look for in an x86
processor?
How would you rank the following in terms of importance for a
processor's performance?
clock speed
cache size
unlocked cores
number of cores
I would probably rank them as listed above.
For a long time now, I've been really happy with an unlocked processor.
The unlocked nature of the processor means it doesn't usually grind
away at a task for a long time, but it finishes in a quick blip, even
though it's only a dual-core. In other words, it seems that processor
speed - both raw clock speed and extra speed from the unlocked cores -
is far more important than having more cores. From earlier processors,
it seemed that a bigger cache was the next biggest improvement after
clock speed. But, of course, this processor is a decade or so old now.
I'm sure you guys have moved on to newer hardware. What are your
thoughts on this? Has much changed in regards to this over the past
decade?

power consumption became an issue now.
the fastest CPU is pretty worthless if Bus/Ram/IO are slow.
more cores than real existing physical memory channels are useless.
So I use only two respective four cores and power down the rest.
larger LVL1 cache would be fine but eat more power and money too.
__
wolfgang

[Branimir Maksimovic]

Post by Rod Pemberton
Hey guys, I'm curious, what features do you look for in an x86
processor?

Luckily for x86 Apple won't give M1 to others :P