Can I use Unbuffered ECC memory with a non-ECC CPU?

Question

I am working on a player controller and having trouble with limiting the character's velocity. The character seems to accelerate indefinitely.

I am updating the character's velocity using rb.AddForce(movement * movementSpeed, ForceMode.VelocityChange), where movement is a normalized Vector3 (with values only for x and z) and movementSpeed is a public float giving the desired movement speed. I realize that it would be trivial to cap the character's velocity by setting it directly but I'm under the impression that setting rb.velocity directly is bad practice (which I'm not entirely sure is true).

My fixed update function:

private void FixedUpdate()
{
    Vector3 movement = new Vector3(Input.GetAxis("Horizontal"), 0f, Input.GetAxis("Vertical"));
    movement.Normalize();
    rb.AddForce(movement * movementForce, ForceMode.VelocityChange);
}

I have tried adding a conditional statement checking if the velocity is greater than the desired maximum and, if true, adding a force in the opposing direction. This results in stuttering. The character's velocity is reset to 0 and forced to accelerate again.

    Vector3 currMovement = new Vector3(rb.velocity.x, 0f, rb.velocity.z);
    float currMagnitude = currMovement.magnitude;
    if (currMagnitude > movementSpeed) {
        rb.AddForce(currMovement * (-1 * movementSpeed / currMagnitude), ForceMode.VelocityChange);
    }

Any help would be greatly appreciated?

TL;DR

• How to cap velocity when using rb.AddForce(movement, ForceMode.VelocityChange)?
• Do I even need to use rb.AddForce or can I directly set rb.velocity?

Solution 1

After testing the i5-3350P with a Kingston KVR13E9/8HM unbuffered ECC memory module, I can confirm that it does not POST at all, and the same 5 short beeps + 1 long beep memory error occurs.

It is now running functionally with a Xeon E3-1220.

Thank you for your input on this matter.

Solution 2

Well, is your server working right now with the i5 processor? Yes or No?

According to your motherboard spec's and the chipset, the i5 CPU is not compatible. Moreover, your mobo supports only ECC memory as you know your CPU doesn't support ECC so it may not work as the recent processors have MC's(memory controller) built into the CPU. This means that the CPU needs to manage the memory. Unbuffered memory requires that the CPU manage all of the chips.

Also check the following Memory configuration guide according to Intel which clears points that i5 and i7 processors are "not supported" though they are of the same socket. (refer page 5 - Intel® C200 Series Chipset Memory Support). Sometimes the system may still boot but YMMV regardless of ECC - techie007. That's just my opinion.

But there is a reason for you to keep your hopes up as this FAQ answered by SUPERMICRO says it should work - Check this link. Let us know if it works out.

Hope that helps.

Comments

[Ƭᴇcʜιᴇ007]

What happened when you tried it?

[Pedro Melo]

I currently have non-ECC memory and I need to exchange that.

[Ƭᴇcʜιᴇ007]

So that motherboard requires unbuffered ECC.. Are you sure that CPU model is compatible with that motherboard? If so, then you should be good, right? :)

[Pedro Melo]

It is not officially, but I believe that is due to the i5 not having ECC support. It is indeed the correct socket however.

[Ƭᴇcʜιᴇ007]

Uhh, yeah.. Can it work with ECC RAM, probably depends on the motherboard. Since you're using a board that doesn't list that CPU as compatible, then YMMV regardless of ECC. So I'm not going to try and answer this. Good luck. :(

[Ruzihm]

Setting rb.velocity directly is not bad practice if you already can calculate what the rigidbody velocity ought to be at the current frame, and the presence or absence of other colliders, gravity, or other physics considerations are meant to be irrelevant in that calculation.

[Ruzihm]

Mind that when clamping components separately, it will generally result in a "box"-like clamping rather than a circular clamping one might prefer.

[AdrAs]

Here's a good answer when to use AddForce and when to set velocity directly. And here's an answer on how to clamp the velocity