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I was on the verge of buying a new computer when meltdown and spectre were made public. I've read about how the software fix can cause a 5 to 30% slowdown. In light of that, I would like to buy a professor that is unaffected. I assume Intel still does not have a new processor that is unagfected. Is there a safe processor yet, or do I need to wait?

I haven't been able to find any information on when the processor companies will have unaffected processors.

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TL;DR: Wait a little while.

First, let's be clear: there are two tightly connected but separate vulnerabilities here. Meltdown is specific to Intel CPUs since 1995 and has already been patched on all three major OSs, while Spectre is present on almost all x86 chips (AMD and Intel) and ARM chips. Though I won't go too in depth, as of yet there is no universal solution, hardware or software, that universally patches Spectre. I strongly recommend reading this briefing and–if you have at least some background in CS/are willing to spend a lot of time learning about the low level architecture–the Project Zero blog and whitepapers released by the researching groups.

Regarding Meltdown: I've seen those numbers and–while I don't doubt there will be a performance hit–I'm dubious. Be very wary of any answers you recieve here, including my own (I have a limited background in CS, but I haven't come close to fully digesting all the information out there.) Because of the nature of Meltdown's attack vector and subsequent patch, the performance hit is hardest in syscall heavy workloads, but is implementation and workload dependent. I'm going to refrain from quoting any hard numbers simply because of the quantity of numbers out there (Google "meltdown performance" and you'll see workloads ranging from SQL performance within a Linux guest OS on a type-1 hypervisor to Windows Unigine Superposition benchmarks), but I'd expect these numbers to go down over the course of the coming weeks/months. Where this ends is just too difficult to say right now.

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    Can confirm (or at least add a second voice to) this. Typical-user workloads won't see anywhere near the slowdown that the current articles are quoting, though I can't give you exact numbers. – ArtOfCode Jan 6 '18 at 18:51
  • My one benchmark for Meltdown (compiling the Linux kernel) showed a 3% slowdown from KPTI (the Linux mitigation). I've seen gaming benchmarks showing about a 5% slowdown. For the average user doing average things, the performance hit won't be noticeable. – Mark Jan 8 '18 at 21:23
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If you're worried about Meltdown (the easier of the two vulnerabilities to exploit), buy anything AMD. Meltdown is an Intel-only issue.

If you want to avoid both, you've got very few options. About the only consumer-level CPUs that aren't vulnerable to Spectre are the "Bonnell"-series Intel Atom CPUs and the lower-end ARM CPUs. If you want to buy something pre-assembled, you're pretty much stuck with a first-generation Chromebook off Ebay: the Google CR-48, Samsung Series 5, or Acer AC700.

Personally, I recommend waiting.

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Intel does not have a released processor that is unaffected by meltdown. AMD claims that it is unaffected by meltdown.

However, benchmarks have been released by numerous sites and the real world implications of the software patch aren't really that concerning to the average user. For example, looking at the benchmarks from techspot they found that the performance decrease in games range from 0% to 4%, while some things like blender and excel were unaffected by it.

The big performance hit is if you do continuous writes at 512K and lower with an ssd which gives you up to a 40% performance hit, while reads slowed down by up to 17%.

If you are using your computer normally without expecting to heavily read and write files like hosting a database, then you won't notice a significant performance decrease. Even if you wait a little bit it will take time, perhaps over a year, before companies solve this problem on a hardware level and then tool machines to produce them. If you want to avoid the meltdown patch you can get an AMD processor and not patch your windows computer, however you should wait a bit to see if AMD's claims are true.

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    While AMD CPUs could be unaffected by Meltdown, it should be noted that they are still vulnerable to Spectre. Spectre might be harder to exploit and does not disclose kernel memory, there isn't, and won't be, a software patch. A firmware update, at the minimum, would be required. (Though, I guess that does mean that there is no issue with the software patch causing performance degradation, since there isn't one) – timuzhti Jan 8 '18 at 13:13
  • AMD claims that the fix will have negligible impact on performance. Also everyone is essentially affected by Spectre, so if you're looking for a computer you shouldn't worry too much about it because if a hardware revision is needed it probably won't be out until next year at the earliest. – Kaito Jan 8 '18 at 15:43

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