Spread spectrum has proved effective in lowering EMI and will benefit the industry if it becomes more more available. Spread-spectrum timing generation does not have the drawbacks of traditional methods. Adding ground planes to lower EMI increases the cost of a design.
Metallic casing adds too much weight for portable applications.
There are also drawbacks to adding passive components or changing the values of existing passives to adjust edge rates have their drawbacks. As system speeds rise, timing budgets become constrained, preventing designers from altering the edge rate too drastically. In other applications, heavier spread spectrum has been shown to reduce noise by as much as 20 dB on some harmonics. And all harmonics benefit at the same time, whereas the addition of passives just shifts the energy from one harmonic to another. When Intel Corp. supported spread-spectrum with the Pentium II and the BX chip set, PC makers were able to see the benefits and adopt the technique as a standard in clocking architectures.